build(deps): bump flutter_local_notifications

Bumps [flutter_local_notifications](https://github.com/MaikuB/flutter_local_notifications) from 14.1.2 to 15.1.0+1.
- [Release notes](https://github.com/MaikuB/flutter_local_notifications/releases)
- [Commits](MaikuB/flutter_local_notifications@flutter_local_notifications-v14.1.2...flutter_local_notifications-v15.1.0)

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

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

packages/notification_sender/pubspec.yaml

@@ -10,7 +10,7 @@ environment:
 dependencies:
   flutter:
     sdk: flutter
-  flutter_local_notifications: ^14.0.0+1
+  flutter_local_notifications: ^15.1.0+1
   riverpod: ^2.3.7
   riverpod_annotation: ^2.1.2
   timezone: ^0.9.0