Pin mkdocs version to avoid error

Author: nseidle

.github/workflows/mkdocs.yml

@@ -10,6 +10,6 @@ jobs:
       - uses: actions/checkout@v3
       - uses: actions/setup-python@v4
         with:
-          python-version: 3.12.0
-      - run: pip install mkdocs-material mkdocs-monorepo-plugin
+          python-version: 3.x
+      - run: pip install mkdocs-material==9.4.9 mkdocs-monorepo-plugin
       - run: mkdocs gh-deploy --force