add: added a workflow for PR approval

.github/workflows/node.js.pr.yml

@@ -0,0 +1,26 @@
+name: Build site
+
+on:
+  pull_request:
+    types: [opened, reopened]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    environment: github-pages
+
+    strategy:
+      matrix:
+        node-version: [16.x]
+
+    steps:
+    - uses: actions/checkout@v2
+    - name: Use Node.js ${{ matrix.node-version }}
+      uses: actions/setup-node@v2
+      with:
+        node-version: ${{ matrix.node-version }}
+        cache: 'npm'
+    - name: Installing dependencies
+      run: npm install
+    - name: Build the website
+      run: npm run build