I have upgraded the underlying version of PyGithub to fix a github connectivity issue. You can still install the script from: https://gist.github.com/4026453.
Note that this script attempts to delete directories (Folders) called 'temp' and 'dateutil' within Pythonista as part of installation. It will also overwrite files in directories named 'github' and 'githubista'. If you are using Pythonista 1.3 or above please check that you have not created any Folders with these names before running this script as any files inside them will be irretrievably lost.