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@7.1.9...9.1.8)

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

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

Author: dependabot[bot]

pyproject.toml

@@ -96,7 +96,7 @@ all = [
 ]
 doc = [
     "mkdocs >=1.1.2,<2.0.0",
-    "mkdocs-material >=7.1.9,<9.0.0",
+    "mkdocs-material >=7.1.9,<10.0.0",
     "mdx-include >=1.4.1,<2.0.0",
     "mkdocs-markdownextradata-plugin >=0.1.7,<0.3.0",
     "markdown-include",