Fixes for Makefile
Fixes for Makefile

- Set default mock configuration to epel-8-x86_64, to match the
  default dist value.
- Add support for alpha tags, like the recently added v5.0.0alpha1

Signed-off-by: Javier Pena <430b5df70471658abbd4d9a6eb8b63e34d90b90a@redhat.com>

ceph/ceph-ansible,ceph/ceph-ansible