[SSSD] [sssd PR#5784][opened] proxy: allow removing group members

[ikerexxe]

URL: https://github.com/SSSD/sssd/pull/5784
Author: ikerexxe
 Title: #5784: proxy: allow removing group members
Action: opened

PR body:
"""
The proxy provider doesn't allow to remove group members once they have
been added. This patch allows to do it by looping the member list from
the cache and comparing it with the actual membership list. If a member
is missing then it's removed from the cache.

Resolves: https://github.com/SSSD/sssd/issues/5783
"""

To pull the PR as Git branch:
git remote add ghsssd https://github.com/SSSD/sssd
git fetch ghsssd pull/5784/head:pr5784
git checkout pr5784