PROTON-2254 Update proton-cpp CMake install to also use new features#330

jiridanek merged 3 commits intoapache:mainapache/qpid-proton:mainfrom

jiridanek:jd_2021_05_13_PROTON-yyyy_staticjiridanek/qpid-proton:jd_2021_05_13_PROTON-yyyy_staticCopy head branch name to clipboard