Add GitHub Actions deploy

Author: noriwanne

.github/workflows/deploy.yml

@@ -0,0 +1,30 @@
+name: Deploy VitePress site
+
+on:
+  push:
+    branches:
+      - main
+
+jobs:
+  build-and-deploy:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Setup Node
+        uses: actions/setup-node@v4
+        with:
+          node-version: 20
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Build VitePress site
+        run: npx vitepress build
+
+      - name: Deploy to GitHub Pages
+        uses: peaceiris/actions-gh-pages@v3
+        with:
+          github_token: ${{ secrets.GITHUB_TOKEN }}
+          publish_dir: .vitepress/dist