Fix Github Actions docs pipeline (#1622)

.github/workflows/docs.yml

@@ -26,7 +26,7 @@ jobs:
           key: ${{ github.ref }}
           path: .cache
       - name: Setup dependencies
-        run: pip install mkdocs-material pillow cairosvg mkdocs-minify-plugin
+        run: pip install -r docs/requirements.txt
       - name: Build docs
         run: mkdocs build --strict
       - name: Upload artifact