bump cloud_base disk size to 5gb from 4gb
    
    We really need to figure out whats grown here, but in the mean time we
    just need to get a compose out, so increase the size here.
    
    The aarch64 one went past 4gb.
    see: https://koji.fedoraproject.org/koji/taskinfo?taskID=56316220
    
    Signed-off-by: Kevin Fenzi <kevin@scrye.com>