swagger_parser Wrong JsonKey generated

Steps to reproduce

generate Swagger with the following config:

swagger_parser:
  enums_to_json: true
  schema_path: api.json 
  output_directory: lib/api 
  language: dart Default: dart
  json_serializer: freezed

global_options:
 freezed:
   runs_before:
     - json_serializable
 json_serializable:
   runs_before:
     - retrofit_generator

The JsonKey is wrong. It should start with a lowercase letter or even be omitted. I checked the previous versions and it seems to be related to the 1.18.0 version

Expected results

@Freezed()
class MenuItem with _$MenuItem {
  const factory MenuItem({
    required String title,
    required LinkOptions linkOptions,
  }) = _MenuItem;
  
  factory MenuItem.fromJson(Map<String, Object?> json) => _$MenuItemFromJson(json);
}

Actual results

@Freezed()
class MenuItem with _$MenuItem {
  const factory MenuItem({
    required String title,
    @JsonKey(name: 'LinkOptions')
    required LinkOptions linkOptions,
  }) = _MenuItem;
  
  factory MenuItem.fromJson(Map<String, Object?> json) => _$MenuItemFromJson(json);
}

Your OpenApi snippet

  "components": {
    "schemas": {
      "MenuItem": {
        "type": "object",
        "required": ["title"],
        "properties": {
          "title": { "type": "string", "example": "Test 123" },
          "linkOptions": { "$ref": "#/components/schemas/linkOptions" }
        }
      },
      "linkOptions": {
        "type": "object",
        "required": ["type", "title"],
        "properties": {
          "type": {
            "enum": ["internal", "external"],
            "type": "string",
            "example": "internal"
          }
        }
      }
    }
  },