I've answered this numerous times in this thread, but I'll say it again, very loudly and very definitively: WE DO NOT WRITE TO YOUR SSH KEYS, EVER. EVER. EVER. We don't even read them.
Unfortunately, as beautiful as GitHub's API is, they've got their scopes for permissions completely wrong and we know they are working to fix this.
Short answer: https://gitter.zendesk.com/hc/en-us/articles/200178961-Why-d...
Long answer: https://gitter.zendesk.com/hc/en-us/articles/200176672-Authe...
Mike