gitlab-ci: Run krb5 tests also with MIT Kerberos 1.20 (prerelease)
This adds test against MIT Kerberos 1.20 (prerelease) in order to test
Bronze Bit, S4U and RBCD functionality supported only in current MIT Kerberos
git master. We created a Fedora COPR package for MIT KRB5 1.20 (prerelease).
MIT Kerberos 1.20 will be released in autumn 2022. As soon as MIT Kerberos 1.20
will be in a Fedora release, these runners will be removed again.
Signed-off-by: Andreas Schneider <asn@samba.org>
Reviewed-by: Stefan Metzmacher <metze@samba.org>