chore(deps): update dependency flutter_lints to v6

Author: renovate[bot]

pubspec.yaml

@@ -17,7 +17,7 @@ dependencies:
 dev_dependencies:
   flutter_test:
     sdk: flutter
-  flutter_lints: ^5.0.0
+  flutter_lints: ^6.0.0
   network_image_mock: ^2.0.1
 
 # For information on the generic Dart part of this file, see the