Release documentation and process

[TommyCpp]

We need to document the release process to help us release more frequently. We should have a step-by-step guide to release a create

[TommyCpp]

#1327 should help us release more confidently

[jtescher]

Working on getting github group access for @open-telemetry/rust-maintainers on crates.io, at that point we can document how any maintainer can run the release process. (at this point it's just running cargo publish)

[hdost]

Update from the SIG meeting @jtescher is working with Community Managers to allow access so that the github group can be used to add users to crates.io

[hdost]

I saw just a couple days ago that the org should now be readable by crates.io

open-telemetry/community#1938 is completed.

[hdost]

The release process could be something like:

• Check pending PRs and validate if they should be a blocker for a next release (merge as necessary)
• Create a release PR
  • For each crate
    • Bump appropriate version
    • Update change logs to reflect
    • update API/SDK version as necessary
• Merge the PR
  • Get reviews from other Maintainers
  • Ensure that there haven't been any interfering PRs
• Tag the release commit (TBD convention)
• Create Github Release
• Publish to crates.io using the version as of the release commit
  • TBD include steps or links cargo release
• Post to #otel-rust on CNCF Slack.

[cijothomas]

We have the process documented and have been following it for last few releases without trouble. Closing this issue.