We have made a few changes to both GEMS and GMML GitHub repositories. He have created a new "stable" branch, which is a copy of master, and removed master. For anyone who pulls directly from the master branch. they will need to change where their local repository pulls from now in order to keep getting the latest stable code. It is quite simple to make this change, here is a good Stack Overflow question and answer with multiple ways to achieve this.
TL;DR The syntax to change local master to track with origin stable is "$ git branch master --set-upstream-to=origin/stable"