Remove mkdocs-material-extensions

The mkdocs-material-extensions package is now deprecated, and it is
now integrated into mkdocs-material 9.4.

Author: gcs278

requirements.txt

@@ -11,7 +11,6 @@ mkdocs==1.6.1
 mkdocs-awesome-pages-plugin==2.10.1
 mkdocs-macros-plugin==1.3.7
 mkdocs-material==9.6.7
-mkdocs-material-extensions==1.3.1
 mkdocs-redirects==1.2.2
 mkdocs-mermaid2-plugin==1.2.1
 pandas>=2.0.3