prefix this with
git checkout master git pull origin master # git reset --hard origin/master perhaps too aggressive
just in case you're doing this in batch right now and maybe forgot to check which branch you had checked out locally before executing.
(I know this gist is from 6 years ago but it was the top Google hit when I searched for "rename master branch github")
Without git push -u / --set-upstream your local newname branch would keep tracking origin/master, which you