Add Windows Emscripten build of xeus-cpp to ci#647

mcbarton wants to merge 5 commits intocompiler-research:maincompiler-research/CppInterOp:mainfrom

mcbarton:Add-Windows-Emscripten-build-of-xeus-cpp-to-cimcbarton/CppInterOp:Add-Windows-Emscripten-build-of-xeus-cpp-to-ciCopy head branch name to clipboard