docs(readme): remove token from CircleCI status badge after open source

[mwbrooks]

Summary

This pull request updates the README.md by removing the token from the CircleCI status badge. The token was required for private repos, but no longer required because we've now a public, open sourced project 🎉 🥳

The token is only used for the status badge, so there's no security concern that it's part of our commit history.

Reviewers

• Preview README.md
  • If you're logged into CircleCI, you can open this link in an Incognito browser window

Requirements

• 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 62.95%. Comparing base (1482e2e) to head (9644370).
Report is 8 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #23      +/-   ##
==========================================
+ Coverage   62.79%   62.95%   +0.16%     
==========================================
  Files         210      210              
  Lines       22053    22127      +74     
==========================================
+ Hits        13848    13930      +82     
+ Misses       7126     7111      -15     
- Partials     1079     1086       +7     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[zimeg]

@mwbrooks LGTM and thank you for keeping a note of this change. This is another link for my bookmarks 🏷️✨

[mwbrooks]

Thanks for the eyes @zimeg! If you have a way for SVG badges to appear on browser bookmarks, I wanna see it! 📛