Add the auto publish action when released the package

.github/workflows/publish.yml

@@ -0,0 +1,22 @@
+name: Publish
+
+on:
+  release:
+    types: [published]
+  workflow_dispatch:
+
+jobs:
+  publish:
+
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v1
+      - name: Publish
+        uses: sakebook/actions-flutter-pub-publisher@v1.3.0
+        with:
+          credential: ${{ secrets.CREDENTIALS }}
+          flutter_package: true
+          skip_test: true
+          dry_run: false