Add GitHub Pages deployment workflow

.github/workflows/deploy.yml

@@ -0,0 +1,19 @@
+name: Deploy to GitHub Pages
+
+on:
+  push:
+    branches:
+      - main
+
+jobs:
+  deploy:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: write
+    steps:
+      - uses: actions/checkout@v3
+      - name: Deploy to GitHub Pages
+        uses: peaceiris/actions-gh-pages@v3
+        with:
+          publish_dir: .
+