Bump @primer/css from 21.0.9 to 21.2.2 (#393)

Bumps [@primer/css](https://github.com/primer/css) from 21.0.9 to 21.2.2.
- [Release notes](https://github.com/primer/css/releases)
- [Changelog](https://github.com/primer/css/blob/main/CHANGELOG.md)
- [Commits](primer/css@v21.0.9...v21.2.2)

---
updated-dependencies:
- dependency-name: "@primer/css"
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

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