Bump postcss, css-loader, optimize-css-assets-webpack-plugin, postcss…

…-loader and postcss-preset-env

Bumps [postcss](https://github.com/postcss/postcss) to 8.4.32 and updates ancestor dependencies [postcss](https://github.com/postcss/postcss), [css-loader](https://github.com/webpack-contrib/css-loader), [optimize-css-assets-webpack-plugin](https://github.com/NMFR/optimize-css-assets-webpack-plugin), [postcss-loader](https://github.com/webpack-contrib/postcss-loader) and [postcss-preset-env](https://github.com/csstools/postcss-plugins/tree/HEAD/plugin-packs/postcss-preset-env). These dependencies need to be updated together.


Updates `postcss` from 7.0.36 to 8.4.32
- [Release notes](https://github.com/postcss/postcss/releases)
- [Changelog](https://github.com/postcss/postcss/blob/main/CHANGELOG.md)
- [Commits](postcss/postcss@7.0.36...8.4.32)

Updates `css-loader` from 2.1.1 to 6.8.1
- [Release notes](https://github.com/webpack-contrib/css-loader/releases)
- [Changelog](https://github.com/webpack-contrib/css-loader/blob/master/CHANGELOG.md)
- [Commits](webpack-contrib/css-loader@v2.1.1...v6.8.1)

Updates `optimize-css-assets-webpack-plugin` from 5.0.1 to 6.0.1
- [Commits](NMFR/optimize-css-assets-webpack-plugin@v5.0.1...v6.0.1)

Updates `postcss-loader` from 3.0.0 to 7.3.3
- [Release notes](https://github.com/webpack-contrib/postcss-loader/releases)
- [Changelog](https://github.com/webpack-contrib/postcss-loader/blob/master/CHANGELOG.md)
- [Commits](webpack-contrib/postcss-loader@v3.0.0...v7.3.3)

Updates `postcss-preset-env` from 6.6.0 to 9.3.0
- [Changelog](https://github.com/csstools/postcss-plugins/blob/main/plugin-packs/postcss-preset-env/CHANGELOG.md)
- [Commits](https://github.com/csstools/postcss-plugins/commits/HEAD/plugin-packs/postcss-preset-env)

---
updated-dependencies:
- dependency-name: postcss
  dependency-type: indirect
- dependency-name: css-loader
  dependency-type: direct:development
- dependency-name: optimize-css-assets-webpack-plugin
  dependency-type: direct:development
- dependency-name: postcss-loader
  dependency-type: direct:development
- dependency-name: postcss-preset-env
  dependency-type: direct:development
...

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