Bump postcss, postcss-loader and postcss-preset-env

Bumps [postcss](https://github.com/postcss/postcss) to 8.4.49 and updates ancestor dependencies [postcss](https://github.com/postcss/postcss), [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 7.0.39 to 8.4.49
- [Release notes](https://github.com/postcss/postcss/releases)
- [Changelog](https://github.com/postcss/postcss/blob/main/CHANGELOG.md)
- [Commits](postcss/postcss@7.0.39...8.4.49)

Updates `postcss-loader` from 3.0.0 to 8.1.1
- [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...v8.1.1)

Updates `postcss-preset-env` from 6.7.2 to 10.1.0
- [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: postcss-loader
  dependency-type: direct:development
- dependency-name: postcss-preset-env
  dependency-type: direct:development
...

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