fix bug

src/EventSubscriber/TaskLifecycleSubscriber.php

@@ -98,7 +98,7 @@ class TaskLifecycleSubscriber implements EventSubscriberInterface
         $task->setDoneBy($user);
 
         $task->setChangesetsResult(
-            json_encode($this->osmClient()->getChangesets(
+            json_encode($this->osmClient->getChangesets(
                 $user->getUsername(),
                 $task->getStartAt(),
                 $task->getFinishAt()