Let any contributor to a project update the PR meta-data
Before this we were considering that only people with commit access could
work on PR, but that's not quite true, we should let people with ticket
access be able to triage PR as well and thus edit their meta-data.
Fixes https://pagure.io/pagure/issue/3967
Signed-off-by: Pierre-Yves Chibon <pingou@pingoured.fr>