chore: update GitHub branch references to use HEAD (#929)

Author: thinkingserious

CHANGELOG.md

@@ -152,7 +152,7 @@ All notable changes to this project will be documented in this file.
 
 ### Added
 - Twilio SendGrid branding
-- [Twilio SMS example](https://github.com/sendgrid/sendgrid-python/blob/master/use_cases/sms.md)
+- [Twilio SMS example](use_cases/sms.md)
 - Updated CLA process
 
 ## [6.0.0] - 2019-04-02 ##
@@ -162,7 +162,7 @@ All notable changes to this project will be documented in this file.
 - The `Mail` helper signature has changed.
 - Setting up a `SendGridAPIClient` has changed.
 
-Please see the [use cases documentation](https://github.com/sendgrid/sendgrid-python/blob/master/use_cases/README.md) for implemenation details.
+Please see the [use cases documentation](use_cases/README.md) for implemenation details.
 
 This refactor was based on [this issue](https://github.com/sendgrid/sendgrid-python/issues/347). BIG thanks to all of those who [participated](https://github.com/sendgrid/sendgrid-python/issues/323) in shaping this release. 
 
@@ -198,7 +198,7 @@ In particular, BIG THANKS to:
 - [PR #488](https://github.com/sendgrid/sendgrid-python/pull/488): Fix similar code issue in mail.py helper (BIG thanks to [@adiman9](https://github.com/adiman9))
 - [PR #496](https://github.com/sendgrid/sendgrid-python/pull/496): Fix issues in sendgrid/helpers/mail/mail.py (BIG thanks to [@galihmelon](https://github.com/galihmelon))
 - [PR #510](https://github.com/sendgrid/sendgrid-python/pull/510): Fix similar code issue in sendgrid/helpers/mail/mail.py (BIG thanks to [@nanspro](https://github.com/nanspro))
-- [PR #524](https://github.com/sendgrid/sendgrid-python/pull/524): Fix master failure on travis (relating to ASM raise-assertion). (BIG thanks to [@extemporalgenome](https://github.com/extemporalgenome))
+- [PR #524](https://github.com/sendgrid/sendgrid-python/pull/524): Fix main failure on travis (relating to ASM raise-assertion). (BIG thanks to [@extemporalgenome](https://github.com/extemporalgenome))
 
 ### Added
 - [PR #666](https://github.com/sendgrid/sendgrid-python/pull/666): Created First-timers.md File (BIG thanks to [@jaykay12](https://github.com/jaykay12))
@@ -316,7 +316,7 @@ Removed the trailing white spaces. Big thanks to [Siddaram Halli](https://github
 ## [5.0.0] - 2017-08-11
 ### BREAKING CHANGE
 - The breaking change actually happened in [version 4.2.1](https://github.com/sendgrid/sendgrid-python/releases/tag/v4.2.1), where I mistakenly applied a patch version bump. See issues #328 and #321 for details.
-- This version (5.0.0) replaces error handling via HTTPError from urllib in favor of custom error handling via the [HTTPError class](https://github.com/sendgrid/python-http-client/blob/master/python_http_client/exceptions.py) as was the case in version 4.2.0.
+- This version (5.0.0) replaces error handling via HTTPError from urllib in favor of custom error handling via the [HTTPError class](https://github.com/sendgrid/python-http-client/blob/HEAD/python_http_client/exceptions.py) as was the case in version 4.2.0.
 
 ## [4.2.1] - 2017-08-03 ##
 ### Fixed
@@ -337,7 +337,7 @@ Removed the trailing white spaces. Big thanks to [Siddaram Halli](https://github
 ### BREAKING CHANGE
 - Pull #244 [refactor helpers using property getter/setter](https://github.com/sendgrid/sendgrid-python/pull/244/files)
 - Big thanks to [Denis Vlasov](https://github.com/denis90) for the pull request!
-- The changes break the implementation of the [Mail Helper](https://github.com/sendgrid/sendgrid-python/tree/master/sendgrid/helpers/mail) `Mail()` class
+- The changes break the implementation of the [Mail Helper](sendgrid/helpers/mail) `Mail()` class
 - `set_from()` is now the property `from_email`
 - `set_subject()` is now the property `subject`
 - `set_template_id()` is now the property `template_id`
@@ -426,7 +426,7 @@ Removed the trailing white spaces. Big thanks to [Siddaram Halli](https://github
 ## [3.2.2] - 2016-08-23 ##
 ### Added
 - Table of Contents in the README
-- Added a [USE_CASES.md](https://github.com/sendgrid/sendgrid-python/blob/master/USE_CASES.md) section, with the first use case example for transactional templates
+- Added a [USE_CASES.md](USE_CASES.md) section, with the first use case example for transactional templates
 
 ## [3.2.1] - 2016-08-17 ##
 ### Fixed
@@ -448,7 +448,7 @@ Removed the trailing white spaces. Big thanks to [Siddaram Halli](https://github
 
 ## [3.1.8] - 2016-07-25 ##
 ### Added
-- [Troubleshooting](https://github.com/sendgrid/sendgrid-python/blob/master/TROUBLESHOOTING.md) section
+- [Troubleshooting](TROUBLESHOOTING.md) section
 
 ## [3.1.7] - 2016-07-25 ##
 ### Added

CONTRIBUTING.md

@@ -87,7 +87,7 @@ source .env
 
 #### Execute
 
-See the [examples folder](https://github.com/sendgrid/sendgrid-python/tree/master/examples) to get started quickly.
+See the [examples folder](examples) to get started quickly.
 
 If testing from the root directory of this repo, create a new file (e.g. test.py) and replace `import sendgrid` with `from sendgrid import *`
 
@@ -104,7 +104,7 @@ If testing from the root directory of this repo, create a new file (e.g. test.py
 
 The PR must pass all the tests before it is reviewed.
 
-All test files are in the [`test`](https://github.com/sendgrid/sendgrid-python/test) directory. For the purposes of contributing to this repo, please update the [`test_sendgrid.py`](https://github.com/sendgrid/sendgrid-python/tree/master/test/test_sendgrid.py) file with unit tests as you modify the code.
+All test files are in the [`test`](test) directory. For the purposes of contributing to this repo, please update the [`test_sendgrid.py`](test/test_sendgrid.py) file with unit tests as you modify the code.
 
 The integration tests require a Twilio SendGrid mock API in order to execute. We've simplified setting this up using Docker to run the tests. You will just need [Docker Desktop](https://docs.docker.com/get-docker/) and `make`.
 
@@ -165,7 +165,7 @@ Please run your code through:
 5. Locally merge (or rebase) the upstream development branch into your topic branch:
 
    ```bash
-   git pull [--rebase] upstream master
+   git pull [--rebase] upstream main
    ```
 
 6. Push your topic branch up to your fork:
@@ -175,7 +175,7 @@ Please run your code through:
    ```
 
 7. [Open a Pull Request](https://help.github.com/articles/using-pull-requests/)
-    with a clear title and description against the `master` branch. All tests must be passing before we will review the PR.
+    with a clear title and description against the `main` branch. All tests must be passing before we will review the PR.
 
 ## Code Reviews
 If you can, please look at open PRs and review them. Give feedback and help us merge these PRs much faster! If you don't know how, GitHub has some great [information on how to review a Pull Request](https://help.github.com/articles/about-pull-request-reviews/).

FIRST_TIMERS.md

@@ -54,13 +54,13 @@ Kindly make sure, to check for any duplicate issues raised by fellow contributor
 
 **Step 4:** Commit the changes in logical chunks & add commit messages strictly following [this](http://tbaggery.com/2008/04/19/a-note-about-git-commit-messages.html)
 
-**Step 5:** Run all test locally, [for more info](https://github.com/sendgrid/sendgrid-python/blob/master/CONTRIBUTING.md#testing)
+**Step 5:** Run all test locally, [for more info](CONTRIBUTING.md#testing)
 
-**Step 6:** Locally merge your the upstream development branch into your topic-branch using `git pull [--rebase] upstream master`
+**Step 6:** Locally merge your the upstream development branch into your topic-branch using `git pull [--rebase] upstream main`
 
 **Step 7:** Push the topic branch up to your fork using `git push origin <topic-branch-name>`
 
-**Step 8:** Open a Pull Request with clear title and description against the master branch.
+**Step 8:** Open a Pull Request with clear title and description against the main branch.
 
 <a name="reviews"></a>
 ## Be Patient & Wait for Reviews

README.md

@@ -1,7 +1,7 @@
-![SendGrid Logo](https://uiux.s3.amazonaws.com/2016-logos/email-logo%402x.png)
+![SendGrid Logo](twilio_sendgrid_logo.png)
 
-[![Travis Badge](https://travis-ci.org/sendgrid/sendgrid-python.svg?branch=master)](https://travis-ci.org/sendgrid/sendgrid-python)
-[![codecov](https://img.shields.io/codecov/c/github/sendgrid/sendgrid-python/master.svg?style=flat-square&label=Codecov+Coverage)](https://codecov.io/gh/sendgrid/sendgrid-python)
+[![Travis Badge](https://travis-ci.org/sendgrid/sendgrid-python.svg?branch=main)](https://travis-ci.org/sendgrid/sendgrid-python)
+[![codecov](https://img.shields.io/codecov/c/github/sendgrid/sendgrid-python/main.svg?style=flat-square&label=Codecov+Coverage)](https://codecov.io/gh/sendgrid/sendgrid-python)
 [![Docker Badge](https://img.shields.io/docker/automated/sendgrid/sendgrid-python.svg)](https://hub.docker.com/r/sendgrid/sendgrid-python/)
 [![Email Notifications Badge](https://dx.sendgrid.com/badge/python)](https://dx.sendgrid.com/newsletter/python)
 [![MIT licensed](https://img.shields.io/badge/license-MIT-blue.svg)](./LICENSE.md)
@@ -15,7 +15,7 @@
 
 Version 3.X.X+ of this library provides full support for all SendGrid [Web API v3](https://sendgrid.com/docs/API_Reference/Web_API_v3/index.html) endpoints, including the new [v3 /mail/send](https://sendgrid.com/blog/introducing-v3mailsend-sendgrids-new-mail-endpoint).
 
-This library represents the beginning of a new path for SendGrid. We want this library to be community driven and SendGrid led. We need your help to realize this goal. To help make sure we are building the right things in the right order, we ask that you create [issues](https://github.com/sendgrid/sendgrid-python/issues) and [pull requests](https://github.com/sendgrid/sendgrid-python/blob/master/CONTRIBUTING.md) or simply upvote or comment on existing issues or pull requests.
+This library represents the beginning of a new path for SendGrid. We want this library to be community driven and SendGrid led. We need your help to realize this goal. To help make sure we are building the right things in the right order, we ask that you create [issues](https://github.com/sendgrid/sendgrid-python/issues) and [pull requests](CONTRIBUTING.md) or simply upvote or comment on existing issues or pull requests.
 
 Please browse the rest of this README for further detail.
 
@@ -82,7 +82,7 @@ pip install sendgrid
 
 ## Hello Email
 
-The following is the minimum needed code to send an email with the [/mail/send Helper](https://github.com/sendgrid/sendgrid-python/tree/master/sendgrid/helpers/mail) ([here](https://github.com/sendgrid/sendgrid-python/blob/master/examples/helpers/mail_example.py#L9) is a full example):
+The following is the minimum needed code to send an email with the [/mail/send Helper](sendgrid/helpers/mail) ([here](examples/helpers/mail_example.py#L9) is a full example):
 
 ### With Mail Helper Class
 
@@ -103,11 +103,11 @@ print(response.body)
 print(response.headers)
 ```
 
-The `Mail` constructor creates a [personalization object](https://sendgrid.com/docs/Classroom/Send/v3_Mail_Send/personalizations.html) for you. [Here](https://github.com/sendgrid/sendgrid-python/blob/master/examples/helpers/mail_example.py#L16) is an example of how to add it.
+The `Mail` constructor creates a [personalization object](https://sendgrid.com/docs/Classroom/Send/v3_Mail_Send/personalizations.html) for you. [Here](examples/helpers/mail_example.py#L16) is an example of how to add it.
 
 ### Without Mail Helper Class
 
-The following is the minimum needed code to send an email without the /mail/send Helper ([here](https://github.com/sendgrid/sendgrid-python/blob/master/examples/mail/mail.py#L27) is a full example):
+The following is the minimum needed code to send an email without the /mail/send Helper ([here](examples/mail/mail.py#L27) is a full example):
 
 ```python
 import sendgrid
@@ -170,29 +170,29 @@ print(response.headers)
 <a name="inbound"></a>
 # Processing Inbound Email
 
-Please see [our helper](https://github.com/sendgrid/sendgrid-python/tree/master/sendgrid/helpers/inbound) for utilizing our Inbound Parse webhook.
+Please see [our helper](sendgrid/helpers/inbound) for utilizing our Inbound Parse webhook.
 
 <a name="usage"></a>
 # Usage
 
 - [SendGrid Documentation](https://sendgrid.com/docs/API_Reference/index.html)
-- [Library Usage Documentation](https://github.com/sendgrid/sendgrid-python/tree/master/USAGE.md)
-- [Example Code](https://github.com/sendgrid/sendgrid-python/tree/master/examples)
+- [Library Usage Documentation](USAGE.md)
+- [Example Code](examples)
 - [How-to: Migration from v2 to v3](https://sendgrid.com/docs/Classroom/Send/v3_Mail_Send/how_to_migrate_from_v2_to_v3_mail_send.html)
-- [v3 Web API Mail Send Helper](https://github.com/sendgrid/sendgrid-python/tree/master/sendgrid/helpers/mail) - build a request object payload for a v3 /mail/send API call.
-- [Processing Inbound Email](https://github.com/sendgrid/sendgrid-python/tree/master/sendgrid/helpers/inbound)
+- [v3 Web API Mail Send Helper](sendgrid/helpers/mail) - build a request object payload for a v3 /mail/send API call.
+- [Processing Inbound Email](sendgrid/helpers/inbound)
 
 <a name="use-cases"></a>
 # Use Cases
 
-[Examples of common API use cases](https://github.com/sendgrid/sendgrid-python/blob/master/use_cases/README.md), such as how to send an email with a transactional template.
+[Examples of common API use cases](use_cases/README.md), such as how to send an email with a transactional template.
 
 <a name="announcements"></a>
 # Announcements
 
 Please see our announcement regarding [breaking changes](https://github.com/sendgrid/sendgrid-python/issues/217). Your support is appreciated!
 
-All updates to this library are documented in our [CHANGELOG](https://github.com/sendgrid/sendgrid-python/blob/master/CHANGELOG.md) and [releases](https://github.com/sendgrid/sendgrid-python/releases). You may also subscribe to email [release notifications](https://dx.sendgrid.com/newsletter/java) for releases and breaking changes.
+All updates to this library are documented in our [CHANGELOG](CHANGELOG.md) and [releases](https://github.com/sendgrid/sendgrid-python/releases). You may also subscribe to email [release notifications](https://dx.sendgrid.com/newsletter/java) for releases and breaking changes.
 
 <a name="roadmap"></a>
 # Roadmap
@@ -202,19 +202,19 @@ If you are interested in the future direction of this project, please take a loo
 <a name="contribute"></a>
 # How to Contribute
 
-We encourage contribution to our libraries (you might even score some nifty swag), please see our [CONTRIBUTING](https://github.com/sendgrid/sendgrid-python/blob/master/CONTRIBUTING.md) guide for details.
+We encourage contribution to our libraries (you might even score some nifty swag), please see our [CONTRIBUTING](CONTRIBUTING.md) guide for details.
 
 Quick links:
 
-- [Feature Request](https://github.com/sendgrid/sendgrid-python/blob/master/CONTRIBUTING.md#feature-request)
-- [Bug Reports](https://github.com/sendgrid/sendgrid-python/blob/master/CONTRIBUTING.md#submit-a-bug-report)
-- [Improvements to the Codebase](https://github.com/sendgrid/sendgrid-python/blob/master/CONTRIBUTING.md#improvements-to-the-codebase)
-- [Review Pull Requests](https://github.com/sendgrid/sendgrid-python/blob/master/CONTRIBUTING.md#code-reviews)
+- [Feature Request](CONTRIBUTING.md#feature-request)
+- [Bug Reports](CONTRIBUTING.md#submit-a-bug-report)
+- [Improvements to the Codebase](CONTRIBUTING.md#improvements-to-the-codebase)
+- [Review Pull Requests](CONTRIBUTING.md#code-reviews)
 
 <a name="troubleshooting"></a>
 # Troubleshooting
 
-Please see our [troubleshooting guide](https://github.com/sendgrid/sendgrid-python/blob/master/TROUBLESHOOTING.md) for common library issues.
+Please see our [troubleshooting guide](TROUBLESHOOTING.md) for common library issues.
 
 <a name="about"></a>
 # About