Add cache usage to the node.js starter-workflow

ci/node.js.yml

@@ -1,4 +1,4 @@
-# This workflow will do a clean install of node dependencies, build the source code and run tests across different versions of node
+# This workflow will do a clean install of node dependencies, cache/restore them, build the source code and run tests across different versions of node
 # For more information see: https://help.github.com/actions/language-and-framework-guides/using-nodejs-with-github-actions
 
 name: Node.js CI
@@ -25,6 +25,7 @@ jobs:
       uses: actions/setup-node@v2
       with:
         node-version: ${{ matrix.node-version }}
+        cache: 'npm'
     - run: npm ci
     - run: npm run build --if-present
     - run: npm test