Specify a default C++ standard for generated CMakeLists.txt files

[paradowstack]

Right now in the generated files there is no specified C++ standard so compiler fallbacks to the default version. My recommendation is to use C++20 standard instead.

[kraenhansen]

I haven't dug too deep into this, but I wonder if there's a Gyp native way of setting the C++ standard, which this might accidentally collide with?

[paradowstack]

Great catch! According to this issue there are at least a ways to set C++ standard in the Gyp https://github.com/nodejs/node-can gyp/issues/1662 - looks like it's not unified much. It would be great to detect Gyp standard version and populate a CMake files according to it, or fallback to our default one.