add GitHub Actions workflow for deployment

.github/workflows/deploy.yml

@@ -0,0 +1,31 @@
+name: Deploy to GitHub Pages
+
+on:
+  push:
+    branches:
+      - main
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+    - name: Checkout repository content
+      uses: actions/checkout@v3
+
+    - name: Set up Node.js
+      uses: actions/setup-node@v3
+      with:
+        node-version: '18.x'
+        cache: 'pnpm'
+
+    - name: Install dependencies
+      run: pnpm install
+
+    - name: Build project
+      run: pnpm run build
+
+    - name: Deploy to GitHub Pages
+      run: pnpm run gh-pages
+      env:
+        GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}