feat(core) add processing_language for Response model

Author: jhoudan

src/apis/resources/Response.php

@@ -31,6 +31,7 @@ public function __construct($response) {
     }
 
     $this->language = $response->language;
+    $this->processing_language = $response->processing_language;
     $this->version = $response->version;
     $this->timestamp = $response->timestamp;
     $this->status = $response->status;