build: bump mkdocs-material from 9.5.8 to 9.5.9 in /.github/workflows

Bumps [mkdocs-material](https://github.com/squidfunk/mkdocs-material) from 9.5.8 to 9.5.9.
- [Release notes](https://github.com/squidfunk/mkdocs-material/releases)
- [Changelog](https://github.com/squidfunk/mkdocs-material/blob/master/CHANGELOG)
- [Commits](squidfunk/mkdocs-material@9.5.8...9.5.9)

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

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

.github/workflows/mkdocs-requirements.in

@@ -1,2 +1,2 @@
 mike==2.0.0
-mkdocs-material==9.5.8
+mkdocs-material==9.5.9

.github/workflows/mkdocs-requirements.txt

@@ -13,7 +13,7 @@ markupsafe==2.1.1
 mergedeep==1.3.4
 mike==2.0.0
 mkdocs==1.5.3
-mkdocs-material==9.5.8
+mkdocs-material==9.5.9
 mkdocs-material-extensions==1.3
 packaging==22.0
 paginate==0.5.6