Make compose-id and repo-url to take one or more values
    
    Using nargs='*' help will show something like:
    
    --repo-url [URL [URL ...]]
    
    which reads like the option taking *zero* or more values.
    
    The above is probably incorrect or at least it does not make
    sense from a user point of view, as these options once used
    should take one or more space separated values.
    
    Using nargs='+' will fix the above, and help will show the
    intended usage:
    
    --repo-url URL [URL ...]
    
    Signed-off-by: Hunor Csomortáni <csomh@redhat.com>