Actions: add npm cache (#29765)

.github/workflows/test.yml

@@ -26,6 +26,16 @@ jobs:
       - run: npm --version
       - run: java -version
 
+      - name: Set up npm cache
+        uses: actions/cache@v1
+        with:
+          path: ~/.npm
+          key: ${{ runner.os }}-node-v{{ matrix.node }}-${{ hashFiles('package.json') }}-${{ hashFiles('package-lock.json') }}-${{ hashFiles('.github/workflows/test.yml') }}
+          restore-keys: |
+            ${{ runner.OS }}-node-v{{ matrix.node }}-${{ env.cache-name }}-
+            ${{ runner.OS }}-node-v{{ matrix.node }}-
+            ${{ runner.OS }}-
+
       - name: Install npm dependencies
         run: npm ci