chore(deps): update dependency flutter_lints to v6 (#1161)

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

Author: renovate[bot]

pubspec.yaml

@@ -27,6 +27,6 @@ dependencies:
   web: ^1.1.1
 
 dev_dependencies:
-  flutter_lints: ^5.0.0
+  flutter_lints: ^6.0.0
   flutter_test:
     sdk: flutter