Can't access custom data from notification subscriber #3
Description
As defined by Apple documentation, push notifications can contain custom data in the payload:
https://developer.apple.com/library/content/documentation/NetworkingInternet/Conceptual/RemoteNotificationsPG/CreatingtheNotificationPayload.html#//apple_ref/doc/uid/TP40008194-CH10-SW1
Since PushNotificationHandler only passes aps data to the subscribers, custom data cannot be accessed.
https://github.com/gtsifrikas/PushNotificationHandler/blob/master/PushNotificationHandler/PushNotificationHandler.swift#L84