Add npm cache to GitHub Actions node setup

This commit introduces npm caching within the Github Actions setup in "node.js.yml". This should help in speeding up subsequent builds by storing dependencies that need not be refetched.

.github/workflows/node.js.yml

@@ -24,6 +24,7 @@ jobs:
         uses: actions/setup-node@v3
         with:
           node-version: ${{ matrix.node-version }}
+          cache: 'npm'
       - run: npm ci
         working-directory: ./frontend
       - run: npm run build --if-present