try to fix analyzer

Author: ueman

.github/workflows/build.yml

@@ -14,6 +14,7 @@ jobs:
       - uses: subosito/flutter-action@v1
         with:
           channel: 'stable'
+      - run: flutter pub get
       - run: flutter format -n --set-exit-if-changed .
       - run: flutter analyze
       - run: flutter test --coverage