if the upstream was updated, fork based PRs would be unable to resubmit. this is because the hidden tracking ref was not updated before performing a comparison, it was performed *after*. the ordering of events was incorrect. additionaly, the RepoCompare call was being made against pull.TargetBranch when it should have been against the hidden ref. Signed-off-by: oppiliappan <me@oppi.li>