Due to a github token format change some SDMs may have trouble cloning private repositories

Github made a change in the last few hours to their token format. Previously their app tokens were in the form of v1.token, they are now issued in the form of ghs_token. Atomist SDMs that work with private repos on github.com have a switch in the code to determine what type the token is. This is currently broken resulting in authentication errors. We're working to release a new version of the SDM libraries that handle this new token format.