Make git-pr set up branch for pulling (#570)
Make git-pr set up branch for pulling (#570)

With these changes, the pr/nn branches created by git-pr also support `git pull` to get PR updates.
xsyntrex/git-extras,nicolaiskogheim/git-extras,RichardLitt/git-extras,spacewander/git-extras,Jeff-Lewis/git-extras,tj/git-extras,hickey/git-extras,GuillaumeSeren/git-extras