Build: Bump mkdocs-material from 9.5.19 to 9.5.21 (apache#10272)

Bumps [mkdocs-material](https://github.com/squidfunk/mkdocs-material) from 9.5.19 to 9.5.21.
- [Release notes](https://github.com/squidfunk/mkdocs-material/releases)
- [Changelog](https://github.com/squidfunk/mkdocs-material/blob/master/CHANGELOG)
- [Commits](squidfunk/mkdocs-material@9.5.19...9.5.21)

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

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

site/requirements.txt

@@ -17,7 +17,7 @@
 
 mkdocs-awesome-pages-plugin==2.9.2
 mkdocs-macros-plugin==1.0.5
-mkdocs-material==9.5.19
+mkdocs-material==9.5.21
 mkdocs-material-extensions==1.3.1
 mkdocs-monorepo-plugin @ git+https://github.com/bitsondatadev/mkdocs-monorepo-plugin@url-fix
 mkdocs-redirects==1.2.1