deps: update mkdocs-material requirement

Updates the requirements on [mkdocs-material](https://github.com/squidfunk/mkdocs-material) to permit the latest version.
- [Release notes](https://github.com/squidfunk/mkdocs-material/releases)
- [Changelog](https://github.com/squidfunk/mkdocs-material/blob/master/CHANGELOG)
- [Commits](squidfunk/mkdocs-material@8.2.3...9.2.5)

---
updated-dependencies:
- dependency-name: mkdocs-material
  dependency-type: direct:production
...

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

docs/requirements.txt

@@ -1,4 +1,4 @@
 mkdocs >= 1.2.3, < 1.6
-mkdocs-material >= 8.2.3, < 9.2
+mkdocs-material >= 8.2.3, < 9.3
 mkdocstrings >= 0.18.0, < 1
 mkdocstrings[python] >= 0.18, < 1