Sure, if you measure uptime of your business and dev team by whether you're serving pages. I wouldn't.
If Github being down means you're not fixing your site today, I'd call it a runtime dependency.
If Github being down means you're not fixing your site today, I'd call it a runtime dependency.
(Hint: sans hug of death, because a runtime dependency brought it down.)
Deploying/scaling is somewhere in the middle.