build(deps): bump posthtml from 0.16.5 to 0.16.6

Bumps [posthtml](https://github.com/posthtml/posthtml) from 0.16.5 to 0.16.6.
- [Release notes](https://github.com/posthtml/posthtml/releases)
- [Changelog](https://github.com/posthtml/posthtml/blob/master/changelog.md)
- [Commits](posthtml/posthtml@v0.16.5...v0.16.6)

---
updated-dependencies:
- dependency-name: posthtml
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]