💡add github container repository support

hi.
recently ive had some issues with my ISP and DockerHub specifically, i was thinking that it would be great if you guys added support for the new github container repository. that would absolutely relive most of my headache with dockerhub.

i dont know how difficult that would be or how that would work, so if you'd be kind and dont roast me if im wrong it would be nice 😅

i use portainer in my homelab and have cloudflared on it. updating it is a big hassle since i have to basically VPN my entire homelab just to update this. my other containers use other repositories.

thanks for everything. you guys are the best.