Populates the URL and BugReports fields of a GitHub-using R package with
appropriate links. The GitHub repo to link to is determined from the current
project's GitHub remotes:
If we are not working with a fork, this function expects
originto be a GitHub remote and the links target that repo.If we are working in a fork, this function expects to find two GitHub remotes:
origin(the fork) andupstream(the fork's parent) remote. In an interactive session, the user can confirm which repo to use for the links. In a noninteractive session, links are formed usingupstream.
