Caching the existing github access objects, using the 'owner/repo' values as key
in the cache. (It is not necessary to create a new instance of such an object
for every occurrence of a comment...)
Return a Github object to access the repository via the Github API. If this object has already been created it will return it; if not, it will be created first and stored.
Caching the existing github access objects, using the 'owner/repo' values as key in the cache. (It is not necessary to create a new instance of such an object for every occurrence of a comment...)