chore(deps): bump css-minimizer-webpack-plugin in /docs

Bumps [css-minimizer-webpack-plugin](https://github.com/webpack-contrib/css-minimizer-webpack-plugin) from 4.2.2 to 7.0.0.
- [Release notes](https://github.com/webpack-contrib/css-minimizer-webpack-plugin/releases)
- [Changelog](https://github.com/webpack-contrib/css-minimizer-webpack-plugin/blob/master/CHANGELOG.md)
- [Commits](webpack-contrib/css-minimizer-webpack-plugin@v4.2.2...v7.0.0)

---
updated-dependencies:
- dependency-name: css-minimizer-webpack-plugin
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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