I was setting up a new editor and I was trying the GitHub push workflow.
I committed my changes, pressed "Push" and I got a dialog window to enter my GitHub username and password.
On GitHub I have 2FA set up, so you can't just login using those credentials.
What I had to do was create a personal access token that's tied to the app, with the permission needed.
So I went to the GitHub settings, located Developer Settings:
Clicked Personal access tokens:
Now add a name so you'll remember what this token is for, set the expiration to "No expiration" and enable the repo scope. That's the only one you need:
Save and you'll be able to see the token.
Now enter this token as the password in the username/password dialog window.
You're set.