v6: Support 'flutter_map v3' (#66)

Former-commit-id: b2f253f5a5e2950fc16056e05507d3bfec5de7b6 [formerly ed22848]
Former-commit-id: 7fe1df6f5c64a5dd307c5f96e5c6c3e2611f4f8e

Author: JaffaKetchup

pubspec.yaml

@@ -30,7 +30,7 @@ dependencies:
     sdk: flutter
   flutter_background: ^1.1.0
   flutter_local_notifications: ^9.4.1
-  flutter_map: ^3.0.0-beta.1
+  flutter_map: ^3.0.0
   http: ^0.13.5
   ini: ^2.1.0
   latlong2: ^0.8.0