notify pagure when a branch is retired/unretired in PDC to update the ACL

[tyll]

When a branch is inactive (retired) in PDC, pagure will block commit access to the branch:
https://pagure.io/pagure-dist-git/blob/master/f/dist_git_auth.py#_51-62

It needs to be made sure that pagure is notified whenever the active status changes to make sure the config is up-to-date. This is currently blocked by:
https://pagure.io/pagure/issue/2513