Bump postcss, stylelint-order and web-ext (#149)

Bumps [postcss](https://github.com/postcss/postcss) to 8.4.38 and updates ancestor dependencies [postcss](https://github.com/postcss/postcss), [stylelint-order](https://github.com/hudochenkov/stylelint-order) and [web-ext](https://github.com/mozilla/web-ext). These dependencies need to be updated together.


Updates `postcss` from 8.4.25 to 8.4.38
- [Release notes](https://github.com/postcss/postcss/releases)
- [Changelog](https://github.com/postcss/postcss/blob/main/CHANGELOG.md)
- [Commits](postcss/postcss@8.4.25...8.4.38)

Updates `stylelint-order` from 4.1.0 to 6.0.4
- [Release notes](https://github.com/hudochenkov/stylelint-order/releases)
- [Changelog](https://github.com/hudochenkov/stylelint-order/blob/master/CHANGELOG.md)
- [Commits](hudochenkov/stylelint-order@4.1.0...6.0.4)

Updates `web-ext` from 7.6.2 to 7.11.0
- [Release notes](https://github.com/mozilla/web-ext/releases)
- [Commits](mozilla/web-ext@7.6.2...7.11.0)

---
updated-dependencies:
- dependency-name: postcss
  dependency-type: indirect
- dependency-name: stylelint-order
  dependency-type: direct:development
- dependency-name: web-ext
  dependency-type: direct:development
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]