The issue is that the plugin requires the plugin to be deployed in a case sensitive directory "Github"... which is obviously not what the repo is called.
Yes, you can clone to a specific name, but in experience most don't, and it lends itself to confusion.
I'm actually having a think about a better way of loading plugins so hopefully this won't be a problem forever.
Myself, I deploy to an ext. directory and then symlink the dir... works quite well.