Bump mkdocs from 1.4.3 to 1.5.1

Bumps [mkdocs](https://github.com/mkdocs/mkdocs) from 1.4.3 to 1.5.1.
- [Release notes](https://github.com/mkdocs/mkdocs/releases)
- [Commits](https://github.com/mkdocs/mkdocs/compare/1.4.3...1.5.1)

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

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

requirements.txt

@@ -1,4 +1,4 @@
-mkdocs==1.4.3
+mkdocs==1.5.1
 mkdocs-git-revision-date-localized-plugin==1.2.0
 mkdocs-material==9.1.19
 mkdocs-redirects==1.2.1