Setup publish to GitHub Pages (#185)

.github/workflows/publish.yml

@@ -0,0 +1,22 @@
+name: Publish to GitHub Pages
+
+on:
+  push:
+    branches: [main]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v2
+      - uses: subosito/flutter-action@v1
+        with:
+          channel: beta
+      - run: flutter pub get
+      - run: flutter test
+      - uses: bluefireteam/flutter-gh-pages@v7
+        with:
+          workingDir: example
+          baseHref: /yaru_widgets.dart/
+          webRenderer: canvaskit