added auto-deploy with github actions

.github/workflows/deploy-gh-pages.yml

@@ -0,0 +1,30 @@
+name: Deploy to GitHub Pages
+
+on:
+  push:
+    branches:
+      - main
+
+jobs:
+  build-and-deploy:
+    runs-on: ubuntu-latest
+    steps:
+    - name: Checkout source code
+      uses: actions/checkout@v2
+
+    - name: Set up Node.js
+      uses: actions/setup-node@v2
+      with:
+        node-version: '14'
+
+    - name: Install dependencies
+      run: npm install
+
+    - name: Generate static project
+      run: npm run generate
+
+    - name: Deploy to GitHub Pages
+      uses: peaceiris/actions-gh-pages@v3
+      with:
+        github_token: ${{ secrets.GITHUB_TOKEN }}
+        publish_dir: ./dist  # Nuxt 3's generate command outputs to the `dist` directory by default