Add Clang 12 as CUDA compiler to the CI

[SimeonEhrig]

After removing old Clang from the CI in the PR #1300 , we should also add the latest versions of Clang/LLVM.

Since Clang/LLVM 11, Clang is forward compatible to new CUDA versions: llvm/llvm-project@12fefee
So we should change this line in the CMake from a FATAL_ERROR to a WARNING, if the version is greater than 10.

[BenjaminW3]

I will give it a try (also as non-cuda compilers)

[j-stephan]

#1766 adds clang-14 as CUDA compiler to the CI. Once that is merged this should be next.

[bernhardmgruber]

@SimeonEhrig can you please provide a PR for that change? Thx!

[SimeonEhrig]

Clang 13 and older are disabled in this issue #1857 because they are not fully supported