Bump flutter_lints from 3.0.2 to 6.0.0

Bumps [flutter_lints](https://github.com/flutter/packages/tree/main/packages) from 3.0.2 to 6.0.0.
- [Commits](https://github.com/flutter/packages/commits/flutter_lints-v6.0.0/packages)

---
updated-dependencies:
- dependency-name: flutter_lints
  dependency-version: 6.0.0
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

pubspec.yaml

@@ -24,7 +24,7 @@ dependencies:
     sdk: flutter
 
 dev_dependencies:
-  flutter_lints: '>=2.0.0 <4.0.0'
+  flutter_lints: ">=2.0.0 <7.0.0"
   flutter_test:
     sdk: flutter