chore(deps-dev): bump postcss and @patternfly/documentation-framework

Bumps [postcss](https://github.com/postcss/postcss) and @patternfly/documentation-framework. These dependencies needed to be updated together.

Updates `postcss` from 8.5.8 to 8.5.13
- [Release notes](https://github.com/postcss/postcss/releases)
- [Changelog](https://github.com/postcss/postcss/blob/main/CHANGELOG.md)
- [Commits](postcss/postcss@8.5.8...8.5.13)

Updates `@patternfly/documentation-framework` from 6.10.19 to 6.38.6

---
updated-dependencies:
- dependency-name: postcss
  dependency-version: 8.5.13
  dependency-type: direct:development
- dependency-name: "@patternfly/documentation-framework"
  dependency-version: 6.38.6
  dependency-type: direct:development
...

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Author: dependabot[bot]