Bump postcss, autoprefixer and postcss-cli in /FHTAGN

Bumps [postcss](https://github.com/postcss/postcss) to 8.4.31 and updates ancestor dependencies [postcss](https://github.com/postcss/postcss), [autoprefixer](https://github.com/postcss/autoprefixer) and [postcss-cli](https://github.com/postcss/postcss-cli). These dependencies need to be updated together.


Updates `postcss` from 7.0.39 to 8.4.31
- [Release notes](https://github.com/postcss/postcss/releases)
- [Changelog](https://github.com/postcss/postcss/blob/main/CHANGELOG.md)
- [Commits](postcss/postcss@7.0.39...8.4.31)

Updates `autoprefixer` from 9.8.0 to 10.4.16
- [Release notes](https://github.com/postcss/autoprefixer/releases)
- [Changelog](https://github.com/postcss/autoprefixer/blob/main/CHANGELOG.md)
- [Commits](postcss/autoprefixer@9.8.0...10.4.16)

Updates `postcss-cli` from 7.1.1 to 10.1.0
- [Release notes](https://github.com/postcss/postcss-cli/releases)
- [Changelog](https://github.com/postcss/postcss-cli/blob/master/CHANGELOG.md)
- [Commits](postcss/postcss-cli@7.1.1...10.1.0)

---
updated-dependencies:
- dependency-name: postcss
  dependency-type: indirect
- dependency-name: autoprefixer
  dependency-type: direct:development
- dependency-name: postcss-cli
  dependency-type: direct:development
...

Signed-off-by: dependabot[bot] <support@github.com>