title: How do you remove or change your git user.name from historical github commits?
body: <p>I am concerned about my privacy and don't want my real name appearing on my github commits. I just discovered that github is saving my user.name as the contributor as well as my github username. I have now changed my local git user.name so future commits will be fine. But now I'm wondering how can I go back and change the user.name that did commits previously in a repo on github?</p>