Add TypeScript definitions

[tbjers]

New Feature / Enhancement Checklist

• I am not disclosing a vulnerability.
• I am not just asking a question.
• I have searched through existing issues.

Current Limitation

Type declaration comments are stripped out by Babel.

Feature / Enhancement Description

Add TypeScript definition files as outlined in Creating .d.ts Files from .js files in the TypeScript documentation.

Example Use Case

1. Add type definitions to lib/ directory.
2. Update build step in package.json with && tsc.
3. Definitions will be included when publishing the package.
4. Rejoice.

Alternatives / Workarounds

No alternatives or workarounds exist.

3rd Party References

There is no @types/parse-server-api-mail-adapter package.

[parse-github-assistant]

Thanks for opening this issue!

• 🎉 We are excited about your ideas for improvement!

[parseplatformorg]

🎉 This pull request has been released in version 3.1.0