Add cache steps

.github/workflows/website.yml

@@ -27,10 +27,24 @@ jobs:
         uses: actions/setup-python@v5
         with:
           python-version: 3.12
-
+
+      - name: Set up build cache
+        uses: actions/cache/restore@v4
+        with:
+          key: mkdocs-material-${{ hashfiles('.cache/**') }}
+          path: .cache
+          restore-keys: |
+            mkdocs-material-
+
       - name: Install dependencies
         run: |
           pip install -r requirements-docs.txt
       
       - name: Deploy GitHub Pages
         run: mkdocs gh-deploy --force
+
+      - name: Save build cache
+        uses: actions/cache/save@v4
+        with:
+          key: mkdocs-material-${{ hashfiles('.cache/**') }}
+          path: .cache