Suppose I have originally created a fork of github.com/original/bar and the fork is at github.com/itsme/bar. Now in the meantime github.com/original/bar has been superseded and the new upstream project has become github.com/new/FooBar (itself originally forked from original/bar). Is there a chance for me to adjust the settings of my fork so it gets displayed as "forked from new/FooBar" (the new upstream project)? In essence is it possible to "rebase" my fork at the project level as well?
I understand this is mostly cosmetics, but aside from showing up as "forked from original/bar" near the project title my project will continue to show irrelevant information such as:
This branch is X commits ahead, Y commits behind original:master.
... whereas it would be much more sensible to refer to the desired new upstream repository tied to the new upstream project.
Is this at all possible in GitHub without outright deleting my fork and forking from the new upstream project from scratch?
NB: I mean the project indeed, not the contained Git repository. So no need to tell me about, say, this method or refer me here.