freeipa-pr-ci: enable pull-request CI
    
    This config file defines jobs to be executed as a part of the
    pull-request CI. For more information, see:
    
    https://github.com/freeipa/freeipa-pr-ci
    https://www.freeipa.org/page/V4/Pull-Request_CI
    
    Signed-off-by: Tomas Krizek <tkrizek@redhat.com>
    Reviewed-By: Pavel Vomacka <pvomacka@redhat.com>