ci: add publish workflow

.github/workflows/publish.yml

@@ -0,0 +1,39 @@
+name: Publish to pub.dev
+
+on:
+  push:
+    tags:
+      - '[0-9]+.[0-9]+.[0-9]+*'
+
+# based on dart-lang/setup-dart/.github/workflows/publish.yml@v1
+# custimized for flutter
+
+jobs:
+  publish:
+    name: 'Publish to pub.dev'
+    permissions:
+      id-token: write # Required for authentication using OIDC
+    runs-on: ubuntu-latest
+    steps:
+      # Checkout repository
+      - uses: actions/checkout@v4
+
+      # Setup Dart SDK with JWT token
+      - uses: dart-lang/setup-dart@v1
+        with:
+            sdk: stable
+
+      - name: Setup Flutter
+        uses: subosito/flutter-action@v2
+        with:
+          channel: stable
+
+      # Minimal package setup and dry run checks.
+      - name: Install dependencies
+        run: flutter pub get
+      - name: Publish - dry run
+        run: dart pub publish --dry-run
+
+        # Publishing...
+      - name: Publish to pub.dev
+        run: dart pub publish -f