Bump @csstools/selector-specificity from 2.0.2 to 2.2.0

Bumps [@csstools/selector-specificity](https://github.com/csstools/postcss-plugins/tree/HEAD/packages/selector-specificity) from 2.0.2 to 2.2.0.
- [Changelog](https://github.com/csstools/postcss-plugins/blob/main/packages/selector-specificity/CHANGELOG.md)
- [Commits](https://github.com/csstools/postcss-plugins/commits/HEAD/packages/selector-specificity)

---
updated-dependencies:
- dependency-name: "@csstools/selector-specificity"
  dependency-type: indirect
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>