EPEL8: no package.cfg in new branches
    
    Currently, when a maintainer requests an epel8 branch,
    they also get an epel8-playground branch,
    and a package.cfg file is put in their epel8 branch.
    
    The EPEL Steering Committee has agreed on a new vision for EPEL8 Playground,
    that doesn't include automatic building of all epel8 packages.
    This removes the step that adds package.cfg to the epel8 branch.
    
    So, when a maintainer requests an epel8 branch,
    they also get an epel8-playground branch,
    but that's it.
    No package.cfg is added to either branch.
    
    Fixes https://pagure.io/fedora-infrastructure/issue/9322
    Fixes https://pagure.io/fedscm-admin/issue/48