Bump mkdocs-material from 9.1.18 to 9.1.20

Bumps [mkdocs-material](https://github.com/squidfunk/mkdocs-material) from 9.1.18 to 9.1.20.
- [Release notes](https://github.com/squidfunk/mkdocs-material/releases)
- [Changelog](https://github.com/squidfunk/mkdocs-material/blob/master/CHANGELOG)
- [Commits](squidfunk/mkdocs-material@9.1.18...9.1.20)

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

Signed-off-by: dependabot[bot] <[email protected]>

dev_requirements.txt

@@ -2,6 +2,6 @@ black==23.3.0
 isort==5.12.0
 pyright==1.1.316
 mypy==1.4.1
-mkdocs-material==9.1.18
+mkdocs-material==9.1.20
 mkdocstrings==0.22.0
 mkdocstrings[python]==0.22.0