Bump mkdocs from 1.5.3 to 1.6.0 in /.github

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>

Author: dependabot[bot]

.github/workflows/requirements.txt

@@ -2,7 +2,7 @@ colcon-common-extensions==0.3.0
 Markdown==3.6
 markdown-include==0.8.1
 mdx_truly_sane_lists==1.3
-mkdocs==1.5.3
+mkdocs==1.6.0
 pygccxml==2.5.0
 Pygments==2.17.2
 pymdown-extensions==10.7.1