git : reset your branch to the upstream branch

git checkout yourbranch
git remote add upstream https://.......
git fetch upstream
git reset --hard upstream/master
# take care, this will delete all your changes on your forked yourbranch
git push origin yourbranch --force

Source : https://stackoverflow.com/questions/42332769/how-do-i-reset-the-git-master-branch-to-the-upstream-branch-in-a-forked-reposito

https://stackoverflow.com/a/42332860