If you don’t wish to merge a remote branch into your local branch then you can do a force push using:
git push -f origin <branch>
Generally, the origin will be the name of your remote repo.
Note: Usually, the command refuses to update a remote repo that is not an ancestor of the local ref used to overwrite it. This flag disables the check.
This can cause the remote repository to lose commits; use it with care. So use this command with care so that it will push the branches to github.