iOS: Ignore deprecation warning about using UNNotificationPresentationOptionAlert

- XCode could give a deprecation warning about using `UNNotificationPresentationOptionAlert` which is deprecated since iOS 14. The code is already written in such a way that it can only be used on iOS 13 and older versions. So ignore the deprecation warning.

Author: GitToTheHub

src/ios/APPLocalNotification.m

@@ -494,7 +494,10 @@ - (void) userNotificationCenter:(UNUserNotificationCenter *)center
 
  // iOS older then 14: Show notification as banner and in notification center
  } else {
+ #pragma clang diagnostic push
+ #pragma clang diagnostic ignored "-Wdeprecated-declarations"
  presentationOptions |= UNNotificationPresentationOptionAlert;
+ #pragma clang diagnostic pop
  }
  }
  }