Fix deploy yaml

Author: ygao61

.github/workflows/deploy_docs.yaml

@@ -17,7 +17,7 @@ jobs:
       - uses: actions/setup-python@v4
         with:
           python-version: '3.12'
-      - run: pip install mkdocs mkdocs-material
+      - run: pip install mkdocs mkdocs-material mkdocs-include-markdown-plugin
       - run: mkdocs build
       - uses: peaceiris/actions-gh-pages@v3
         with: