Update required version of CMake in ROOTUseFile.cmake
Update required version of CMake in ROOTUseFile.cmake

ROOT already requires CMake 3.9 and makes use of some of its
features in RootMacros.cmake.

root-mirror/root,karies/root,karies/root,karies/root,olifre/root,olifre/root,root-mirror/root,karies/root,olifre/root,olifre/root,olifre/root,olifre/root,root-mirror/root,olifre/root,karies/root,olifre/root,karies/root,karies/root,root-mirror/root,karies/root,root-mirror/root,root-mirror/root,root-mirror/root,karies/root,olifre/root,karies/root,root-mirror/root,karies/root,root-mirror/root,olifre/root,olifre/root,root-mirror/root,root-mirror/root