Convert all DateTimes to UTC during serialization

Author: Rexios80

example/lib/example.g.dart

@@ -66,7 +66,7 @@ Person _$PersonFromJson(Map<String, dynamic> json) => Person(
 Map<String, dynamic> _$PersonToJson(Person instance) => <String, dynamic>{
       'firstName': instance.firstName,
       'lastName': instance.lastName,
-      'dateOfBirth': instance.dateOfBirth?.toIso8601String(),
+      'dateOfBirth': instance.dateOfBirth?.toUtc().toIso8601String(),
     };
 ```
 

example/lib/tuple_example.g.dart

@@ -15,7 +15,7 @@ final bigIntString = ToFromStringHelper(
 
 final dateTimeString = ToFromStringHelper(
   'DateTime.parse',
-  'toIso8601String()',
+  'toUtc().toIso8601String()',
   'DateTime',
 );