fix: undo last minute edit and try to get make checkin clean. Fixed admin.py. Change # noqa: 821 to # noqa: F821 to make ruff ignore undefined variable in the python 2 branch of the code. Hopefully the flake8 run in CI will accept the change from 821 to F821 and not error with an undefined variable.

# https://issues.roundup-tracker.org/issue2551278
# datetime.utcnow deprecated
try:
    from datetime import datetime, UTC

    def utcnow():
        return datetime.now(UTC)

except ImportError:
    from datetime import datetime

    def utcnow():
        return datetime.utcnow()