Bump json_serializable from 6.1.5 to 6.1.6 in /jsonexample (#1088)

Bumps [json_serializable](https://github.com/google/json_serializable.dart) from 6.1.5 to 6.1.6.
- [Release notes](https://github.com/google/json_serializable.dart/releases)
- [Commits](https://github.com/google/json_serializable.dart/compare/json_serializable-v6.1.5...json_serializable-v6.1.6)

---
updated-dependencies:
- dependency-name: json_serializable
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

jsonexample/pubspec.lock

@@ -262,7 +262,7 @@ packages:
       name: json_serializable
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "6.1.5"
+    version: "6.1.6"
   lints:
     dependency: transitive
     description:

jsonexample/pubspec.yaml

@@ -23,7 +23,7 @@ dev_dependencies:
     sdk: flutter
   build_runner: ^2.0.4
   built_value_generator: ^8.0.0
-  json_serializable: ^6.1.5
+  json_serializable: ^6.1.6
   flutter_lints: ^1.0.0
 
 flutter: