Bump stylelint from 15.10.3 to 16.21.0

Bumps [stylelint](https://github.com/stylelint/stylelint) from 15.10.3 to 16.21.0.
- [Release notes](https://github.com/stylelint/stylelint/releases)
- [Changelog](https://github.com/stylelint/stylelint/blob/main/CHANGELOG.md)
- [Commits](stylelint/stylelint@15.10.3...16.21.0)

---
updated-dependencies:
- dependency-name: stylelint
  dependency-version: 16.21.0
  dependency-type: direct:development
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]