revert: Ignore null attributes using @Body() (#225)

* Revert "remove null fields from _data (#222)"

This reverts commit c2b7d76.

* chore: bump version to 1.7.3+5

generator/lib/src/generator.dart

@@ -674,7 +674,6 @@ class RetrofitGenerator extends GeneratorForAnnotation<retrofit.RestApi> {
         blocks.add(refer("$_dataVar.addAll").call([
           refer("${_bodyName.displayName} ?? <String,dynamic>{}")
         ]).statement);
-        blocks.add(Code("$_dataVar.removeWhere((k, v) => v == null);"));
       } else if (_typeChecker(File).isExactly(_bodyName.type.element)) {
         blocks.add(refer("Stream")
             .property("fromIterable")
@@ -700,7 +699,6 @@ class RetrofitGenerator extends GeneratorForAnnotation<retrofit.RestApi> {
             refer("${_bodyName.displayName}?.toJson() ?? <String,dynamic>{}")
           ]).statement);
         }
-        blocks.add(Code("$_dataVar.removeWhere((k, v) => v == null);"));
       } else {
         /// @Body annotations with no type are assinged as is
         blocks

generator/pubspec.yaml

@@ -1,6 +1,6 @@
 name: retrofit_generator
 description: retrofit generator is an dio client generator using source_gen and inspired by Chopper and Retrofit.
-version: 1.3.7+4
+version: 1.3.7+5
 
 homepage: https://mings.in/retrofit.dart/
 repository: https://github.com/trevorwang/retrofit.dart/