chore: Add .github/CODEOWNERS file

[mwbrooks]

Summary

This pull request adds a .github/CODEOWNERS file to adhere to the Salesforce Open Source project requirements.

I've also added the Education team for the docs/ directory (even though the docs directory doesn't exist) and comments to match https://github.com/slackapi/deno-slack-sdk.

Requirements (place an x in each [ ])

• I've read and understood the Contributing Guidelines and have done my best effort to follow them.
• I've read and agree to the Code of Conduct.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 73.01%. Comparing base (b6719c1) to head (479a152).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #118   +/-   ##
=======================================
  Coverage   73.01%   73.01%           
=======================================
  Files          29       29           
  Lines         908      908           
  Branches      141      141           
=======================================
  Hits          663      663           
  Misses        245      245           

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[mwbrooks]

@misscoded Thanks for the approval! 🙇🏻