Update the default jobs for 2.11-git

After the 2.10 release we wanted to increase the minimal compiler versions to test. I propose the following as minimal versions:

• g++-10 with -std=c++20 activated
• clang-13 with -std=c++20 activated and -stdlib=libc++

Both compilers would support c++20 concepts and the concepts library. The gcc-10 compiler is available in debian 11 (bullseye) and ubuntu 20.04, the clang-13 compiler also in debian >= 11, ubuntu >= 22.04 (and it can be installed also in older versions of debian and ubuntu by apt.llvm.org)

Requires docker/ci!147 (merged) to be merged before. (Add clang-13 compiler to the ubuntu 23.04 toolchain)