build(deps): bump mkdocs-material from 9.6.3 to 9.6.4 in /dev

Bumps [mkdocs-material](https://github.com/squidfunk/mkdocs-material) from 9.6.3 to 9.6.4.
- [Release notes](https://github.com/squidfunk/mkdocs-material/releases)
- [Changelog](https://github.com/squidfunk/mkdocs-material/blob/master/CHANGELOG)
- [Commits](squidfunk/mkdocs-material@9.6.3...9.6.4)

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

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

dev/requirements/docs_requirements.txt

@@ -1,3 +1,3 @@
 folium==0.19.4
-mkdocs-material==9.6.3
+mkdocs-material==9.6.4
 mkdocstrings-python==1.15.0