Context:
People have been asking for IPv6 Support on GitHub since years (probably a decade by now)
... and someone even got so annoyed that they decided to setup a dedicated website for checking this: https://isgithubipv6.live/
It's Proton VPN. Lack of IPv6 support is a downer but I wouldn't call them shit.
Edit: maybe elaborate why you deem IPv6 so crucial? As I said: everything works just fine without.