fake-wpilib is now deprecated and should not be used anymore. Instead, we recommend that you use pyfrc, which contains an implementation of fake-wpilib in it, with new features to make working with RobotPy code even easier.
See the pyfrc github site for more info: https://github.com/robotpy/pyfrc
If you really want to use fake-wpilib, just use the following git command to checkout the last commit of fake-wpilib.
$ git checkout archive