chore(deps-dev): Update mkdocs-awesome-pages-plugin requirement

Updates the requirements on [mkdocs-awesome-pages-plugin](https://github.com/lukasgeiter/mkdocs-awesome-pages-plugin) to permit the latest version.
- [Release notes](https://github.com/lukasgeiter/mkdocs-awesome-pages-plugin/releases)
- [Commits](lukasgeiter/mkdocs-awesome-pages-plugin@v2.8.0...v2.9.0)

---
updated-dependencies:
- dependency-name: mkdocs-awesome-pages-plugin
  dependency-type: direct:development
...

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

gh-pages/requirements-dev.txt

@@ -1,4 +1,4 @@
 mkdocs~=1.4.2
-mkdocs-awesome-pages-plugin~=2.8.0
+mkdocs-awesome-pages-plugin~=2.9.0
 mkdocs-material~=9.1.6
 mkdocs-git-revision-date-plugin~=0.3.2