fix callback response

.idea/workspace.xml

       <option name="number" value="Default" />
       <option name="presentableId" value="Default" />
       <updated>1600830685900</updated>
-      <workItem from="1600830687029" duration="2385000" />
+      <workItem from="1600830687029" duration="2597000" />
     </task>
     <servers />
   </component>

src/DummyPayDriver.php

     public function verifyGatewayCallback(Request $request, Response &$response = null): bool
     {
         if($request->query->has('status')){
-            Res::redirectTo($this->return_url);
+            $response = Res::redirectTo($this->return_url);
             return $request->query->get('status') == 'success';
         } else {
             $order_id = $request->query->get('order_id');
                 $this->callback_url.'?'.http_build_query(['order_id' => $order_id, 'status' => 'success']),
                 $this->callback_url.'?'.http_build_query(['order_id' => $order_id, 'status' => 'failed'])
             );
-            Res::make($html);
+            $response = Res::make($html);
             return false;
         }
     }