Fix pip install in mkdocs workflow

.github/workflows/mkdocs.yml

@@ -17,7 +17,7 @@ jobs:
       - uses: actions/setup-python@v5
         with:
           python-version: 3.x
-      - run: pip install -r requirements.txt
+      - run: pip install --no-cache-dir mkdocs mkdocs-material pymdown-extensions
         working-directory: ./mkdocs
       - run: mkdocs gh-deploy --force
         working-directory: ./mkdocs