request-tests-repo: add empty 'upstreamurl' item
    
    This was added to fit with fedscm-admin change. Currently, not
    necessary for functionality.
    
    Relates: https://pagure.io/fedscm-admin/pull-request/37
    Fixes: rhbz#1854987
    
    Signed-off-by: Ondrej Nosek <onosek@redhat.com>