Bump lints from 3.0.0 to 6.0.0

Bumps [lints](https://github.com/dart-lang/core/tree/main/pkgs) from 3.0.0 to 6.0.0.
- [Release notes](https://github.com/dart-lang/core/releases)
- [Commits](https://github.com/dart-lang/core/commits/lints-v6.0.0/pkgs)

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

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

pubspec.yaml

@@ -18,7 +18,7 @@ dependencies:
 dev_dependencies:
   test: ^1.0.0
   dart_jsonwebtoken: ^2.12.2
-  lints: ">=2.1.0 <4.0.0"
+  lints: ">=2.1.0 <7.0.0"
   json_serializable: ^6.7.1
   build_runner: ^2.4.6
   pub_semver: ^2.1.5