build(deps): bump mkdocs from 1.5.3 to 1.6.0 in /docs

Bumps [mkdocs](https://github.com/mkdocs/mkdocs) from 1.5.3 to 1.6.0.
- [Release notes](https://github.com/mkdocs/mkdocs/releases)
- [Commits](mkdocs/mkdocs@1.5.3...1.6.0)

---
updated-dependencies:
- dependency-name: mkdocs
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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