Bump css-loader from 5.0.1 to 5.1.1

Bumps [css-loader](https://github.com/webpack-contrib/css-loader) from 5.0.1 to 5.1.1.
- [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/v5.0.1...v5.1.1

)

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