works now for git repos that have no origin remote

the actions for git-like repos now uses the url of the configured remote
of the master branch, rather than just assuming it's called origin.

Of course this assumes there's a master branch, which perhaps should be a command-line argument, but I think that assuming the master remote is the correct primary remote is valid. I know I have quite a few repositories whose origins I have changed, because that name has no meaning for the first copy of a repository.