This class is meant to be used with your Github hosted WordPress plugins. The purpose of the class is to allow your WordPress plugin to be updated whenever you push out a new version of your plugin; similarly to the experience users know and love with the WordPress.org plugin repository.
The get_plugin_info method is using $args, but below that it uses $response and returns $response, so this won't work.
Either rename $args to $response, or all calls to $response to $args as a solution.