fix update mkdocs CI

.github/workflows/update-mkdocs.yml

@@ -9,7 +9,17 @@ jobs:
   update:
     runs-on: ubuntu-latest
     steps:
-      - name: Update mkdocs
-        run: |
-          pip install mkdocs
-          mkdocs gh-deploy --force
+      name: Checkout code
+        uses: actions/checkout@v2
+
+
+      - name: Set up Python
+        uses: actions/setup-python@v2
+        with:
+          python-version: 3.x
+
+      name: Install dependencies
+        run: pip install mkdocs mkdocs-material
+
+      - name: Deploy GitHub Pages
+        run: mkdocs gh-deploy --force --clean --verbose