I don't think so -- you'll need to do something like a git rebase, and there's no way to do that via the GitHub UI. I know many don't like the 'dirty' history,

I don't think so -- you'll need to do something like a git rebase, and there's no way to do that via the GitHub UI. I know many don't like the 'dirty' history, but I like knowing exactly how the updates made it into my repo.