fix: Add dart-lang/setup-dart for OIDC pub.dev publishing (#66)

Author: rmi22186

.github/workflows/release-publish.yml

@@ -29,10 +29,16 @@ jobs:
     name: Publish and Release
     needs: [build-android, build-ios]
     runs-on: ubuntu-latest
+    permissions:
+      contents: write
+      id-token: write
     steps:
       - name: Checkout repository
         uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
 
+      - name: Setup Dart SDK
+        uses: dart-lang/setup-dart@e51d8e571e22473a2ddebf0ef8a2c4a1885fabab # v1
+
       - name: Setup Flutter
         uses: subosito/flutter-action@1a449444c387b1966244ae4d4f8c696479add0b2 # v2
         with: