Implement Pubsub - 8.9.4 Notifying Entities

Movim is now more and more relying on affiliations management in Pubsub, especially with the Spaces feature.
When affiliations are changed the affiliated JID is not notified of the change, so I can't update the UI properly.

Pubsub have a MAY that would really help with that:
https://xmpp.org/extensions/xep-0060.html#owner-affiliations-notify

Would it be possible to implement it?

Thanks! 