Bump @nextcloud/stylelint-config from 1.0.0-beta.0 to 2.1.2

Bumps [@nextcloud/stylelint-config](https://github.com/nextcloud/stylelint-config) from 1.0.0-beta.0 to 2.1.2.
- [Release notes](https://github.com/nextcloud/stylelint-config/releases)
- [Changelog](https://github.com/nextcloud/stylelint-config/blob/master/CHANGELOG.md)
- [Commits](https://github.com/nextcloud/stylelint-config/commits/v2.1.2)

---
updated-dependencies:
- dependency-name: "@nextcloud/stylelint-config"
  dependency-type: direct:development
  update-type: version-update:semver-major
...

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