python 3.12 deprecated utcnow and utcfromtimestamp

[Boris Bobrov]

In python 3.12 utcnow and utcfromtimestamp have been deprecated: https://github.com/python/cpython/issues/103857 . Keystone uses them extensively:

$ grep -ro "utcnow" . | wc -l | xargs echo "Total matches :"
Total matches : 195

$ grep -ro "utcfromtimestamp" . | wc -l | xargs echo "Total matches :"
Total matches : 12

[Christian Rohmann (christian-rohmann)]

There is / was https://review.opendev.org/c/openstack/keystone/+/906312, unfortunately that was not linked to the bug.