ci: enable k8 upgrade job

The problems with upgrade seem related to dirac-ce, fixed by preventing ce restart.

cvmfs-mkfs job restart also occasionally, but rarely causes an issue, maybe we can add failsafe?

[notice] A new release of pip is available: 23.2.1 -> 26.0.1
[notice] To update, run: pip install --upgrade pip
/var/spool/cvmfs/sw.ctao.dpps.test/rdonly is not mounted properly.
/cvmfs/sw.ctao.dpps.test is not mounted properly.
sw.ctao.dpps.test is in a transaction but /cvmfs/sw.ctao.dpps.test is not mounted read/write
Repository sw.ctao.dpps.test is in a transaction and cannot be repaired.
--> Run `cvmfs_server abort sw.ctao.dpps.test` to revert and repair.
command terminated with exit code 1

Finally there are occasional issues with dirac bootstrap sequence, but that's good to keep seeing and fixing.