Implement npm caching in action.yml

Add caching for npm dependencies in GitHub Actions.

save/action.yml

@@ -21,3 +21,11 @@ runs:
 branding:
   icon: 'archive'
   color: 'gray-dark'
+
+  - name: Cache
+  uses: actions/cache@v5.0.5
+  with:
+    path: ~/.npm                 # Example: paths to cache
+    key: ${{ runner.os }}-node-${{ hashFiles('**/package-lock.json') }}   # Example key
+    restore-keys: |
+      ${{ runner.os }}-node-