next: add release barrier for n-1 of first F41 release

[dustymabe]

With the rollout of F41, set the n-1 build to be a release barrier.

https://docs.fedoraproject.org/en-US/fedora-coreos/update-barrier-signing-keys/

[github-actions]

next
    version: 41.20240916.1.0 (latest)
    start: 2024-09-17 13:00:00+00:00 UTC (in 0:54:20)
           2024-09-17 15:00:00+02:00 Germany/France/Poland
           2024-09-17 10:00:00-03:00 Brazil
           2024-09-17 07:00:00-06:00 Colorado
           2024-09-17 14:00:00+01:00 Ireland
           2024-09-17 09:00:00-04:00 Raleigh/New York/Toronto
           2024-09-17 06:00:00-07:00 Vancouver
    duration: 2880m (48.0h)
stable
    version: 40.20240825.3.0 (latest)
    start: 2024-09-11 03:00:00+00:00 UTC (6 days, 9:05:39 ago)
           2024-09-11 05:00:00+02:00 Germany/France/Poland
           2024-09-11 00:00:00-03:00 Brazil
           2024-09-10 21:00:00-06:00 Colorado
           2024-09-11 04:00:00+01:00 Ireland
           2024-09-10 23:00:00-04:00 Raleigh/New York/Toronto
           2024-09-10 20:00:00-07:00 Vancouver
    duration: 2880m (48.0h)
testing
    version: 40.20240906.2.0 (latest)
    start: 2024-09-11 03:00:00+00:00 UTC (6 days, 9:05:39 ago)
           2024-09-11 05:00:00+02:00 Germany/France/Poland
           2024-09-11 00:00:00-03:00 Brazil
           2024-09-10 21:00:00-06:00 Colorado
           2024-09-11 04:00:00+01:00 Ireland
           2024-09-10 23:00:00-04:00 Raleigh/New York/Toronto
           2024-09-10 20:00:00-07:00 Vancouver
    duration: 2880m (48.0h)