Obsolete old caribou versions (#1568670)
    
    caribou was retired in F28 GA, and then subsequently added back in updates.
    This commit adds obsoletes on old caribou versions, so that they get correctly
    uninstalled on upgrades for Workstation users. Cinnamon that now uses caribou
    will pull new caribou (with higher version number than what's obsoleted here)
    in through dependencies.