Let's update C++ compiler to practice c++20 features

You might say that we practice the first principles and don’t need syntax sugar and fancy features, but I say: “If I want to go fancy with C++, please, let me”

This is discussed a lot: our current strategy is to support the C++ version of the oldest current Ubuntu LTS version to reach the widest base of users. This version is Ubuntu 20.04, which does not fully support C++20. As soon as this version is phased out, we will switch to the next LTS.

I’m not perfectly happy about this, but it was the strategy when I joined the maintainers team and I understand the logic behind it.