chore(deps): bump postcss and sugarss (#91)

Bumps [postcss](https://github.com/postcss/postcss) and [sugarss](https://github.com/postcss/sugarss). These dependencies needed 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 `sugarss` from 2.0.0 to 4.0.1
- [Changelog](https://github.com/postcss/sugarss/blob/main/CHANGELOG.md)
- [Commits](postcss/sugarss@2.0.0...4.0.1)

---
updated-dependencies:
- dependency-name: postcss
  dependency-type: indirect
- dependency-name: sugarss
  dependency-type: indirect
...

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