nullable in body properties

Author: lohanidamodar

src/Spec/Swagger2.php

@@ -251,6 +251,7 @@ public function getMethods($service)
                                     $param['required'] = (in_array($key, $bodyRequired));
                                     $param['example'] = $value['x-example'] ?? null;
                                     $param['isUploadID'] = $value['x-upload-id'] ?? false;
+                                    $param['nullable'] = $value['x-nullable'] ?? false;
                                     $param['array'] = [
                                         'type' => $value['items']['type'] ?? '',
                                     ];