Add GitHub Action to build and deploy to GitHub Pages

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

@@ -0,0 +1,27 @@
+name: Deploy Eleventy to GitHub pages
+
+on:
+  push:
+    branches: [ main ]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        node-version: [20.x]
+    steps:
+      - uses: actions/checkout@v3
+      - name: Setup Node.js ${{ matrix.node-version }}
+        uses: actions/setup-node@v3
+        with:
+          node-version: ${{ matrix.node-version }}
+      - name: Build Eleventy
+        run: |
+          npm install
+          npm run build
+      - name: Deploy 🚀
+        uses: JamesIves/github-pages-deploy-action@v4
+        with:
+          folder: _site
+          branch: gh-pages