Bump css-loader from 5.2.7 to 6.6.0

Bumps [css-loader](https://github.com/webpack-contrib/css-loader) from 5.2.7 to 6.6.0.
- [Release notes](https://github.com/webpack-contrib/css-loader/releases)
- [Changelog](https://github.com/webpack-contrib/css-loader/blob/master/CHANGELOG.md)
- [Commits](https://github.com/webpack-contrib/css-loader/compare/v5.2.7...v6.6.0

)

---
updated-dependencies:
- dependency-name: css-loader
  dependency-type: direct:development
  update-type: version-update:semver-major
...

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