Bump mkdocs-material from 8.3.9 to 9.0.13

Bumps [mkdocs-material](https://github.com/squidfunk/mkdocs-material) from 8.3.9 to 9.0.13.
- [Release notes](https://github.com/squidfunk/mkdocs-material/releases)
- [Changelog](https://github.com/squidfunk/mkdocs-material/blob/master/CHANGELOG)
- [Upgrade guide](https://github.com/squidfunk/mkdocs-material/blob/master/docs/upgrade.md)
- [Commits](https://github.com/squidfunk/mkdocs-material/compare/8.3.9...9.0.13)

Pipfile

@@ -7,7 +7,7 @@ name = "pypi"
 mkdocs = "~=1.4.2"
 mkdocs-build-plantuml-plugin = "~=1.7.4"
 mkdocs-kroki-plugin = "~=0.3.0"
-mkdocs-material = "~=8.3.9"
+mkdocs-material = "~=9.0.13"
 mkdocs-redirects = "~=1.0.3"
 
 [dev-packages]