To access stuff within our VPN at work we have to reset our passwords every 90 days, which often messes me up for a few hours. One such instance is with Github.
Ugh, god damn it.
Easiest way to deal with this is by just deleting your old SSH keys instead of doing anything fancy. You can do this with Mac's Keychain Access.
Delete the appropriate key, and then next you try to push it will ask you for your username and password, and generate a new key for you until you have to reset your password again.