docs: Updated publish workflow

Author: utpal-barman

.github/workflows/publish.yml

@@ -16,6 +16,10 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v3
+      - name: Install Flutter
+        uses: subosito/flutter-action@v2
+        with:
+          channel: 'stable'
       - uses: dart-lang/setup-dart@v1
       - name: Install dependencies
         run: dart pub get