jobs/registry-update-base-images: centos8 -> alma

Follow up on the change of using almalinux instead of centos8 in
docker-playground, with providing the almalinux base images in the
Osmocom registry.

Related: SYS#5818
Related: docker-playground I30e1a773b901b1d2187214445116c7f2aecc4e36
Change-Id: I93a8892da628b8d2f9cbb2a6453e8ab3153a9c4a
1 file changed