add build step

Author: khuyentran1401

.github/workflows/deploy.yml

@@ -14,6 +14,12 @@ jobs:
     steps:
       - name: Checkout
         uses: actions/checkout@v4
+
+      - name: Install dependencies
+        run: npm install
+      - name: Build site
+        run: npm run build
+
       - name: Deploy
         uses: peaceiris/actions-gh-pages@v4
         if: github.ref == 'refs/heads/master'