docs: add publish workflow

Author: bennypowers

.github/workflows/main.yml

@@ -0,0 +1,29 @@
+name: Build and Deploy
+
+on:
+  push:
+    branches:
+      - master   # Only on master now
+
+jobs:
+  build-and-deploy:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout 🛎️
+        uses: actions/checkout@v2
+
+      - name: Setup PNPM
+        uses: pnpm/action-setup@master
+        with:
+          version: latest
+
+      - name: Install and Build 🔧
+        run: |
+          pnpm install
+          pnpm run build
+
+      - name: Deploy 🚀
+        uses: JamesIves/[email protected]
+        with:
+          branch: gh-pages # The branch the action should deploy to.
+          folder: _site # The folder the action should deploy.