Add doc workflow

.github/workflows/doc.yml

@@ -0,0 +1,23 @@
+name: Publish doc
+on:
+  push:
+    branches: [ "main" ]
+permissions:
+  contents: write
+jobs:
+  build-and-deploy:
+    concurrency: ci-${{ github.ref }} # Recommended if you intend to make multiple deployments in quick succession.
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout 🛎️
+        uses: actions/checkout@v3
+
+      - name: Install dependencies
+        run: mix deps.get
+      - name: Build doc
+        run: mix docs
+
+      - name: Deploy 🚀
+        uses: JamesIves/github-pages-deploy-action@v4
+        with:
+          folder: doc # The folder the action should deploy.