chore(deps): update codecov/codecov-action action to v4 (#59)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

.github/workflows/flutter.yml

@@ -41,4 +41,4 @@ jobs:
       - name: Run tests
         run: flutter test --coverage --coverage-path=lcov.info
 
-      - uses: codecov/codecov-action@v3.1.1
+      - uses: codecov/codecov-action@v4.5.0