fix npm version in workflow

.github/workflows/html.yaml

@@ -25,6 +25,9 @@ jobs:
     steps:
       - name: Install node.js
         uses: actions/setup-node@v2
+        with:
+          node-version: '16'
+          cache: 'npm'
       - run: npm install
       - name: Checkout Code
         uses: actions/checkout@v2