Unable to open source file "doctest/doctest.h" and "cxxopts.hpp"

Question

I created a repository from the template provided on

https://github.com/TheLartians/ModernCppStarter

I clone the repo and opened it using CLION and visual studio code. I expected that both the doctest.hpp and cxxopts.hpp will be added automatically (since both packages are available in the CMakeLists.txt. But this is not the case as I get the following errors:

cannot open source file "doctest/doctest.h"     
cannot open source file "cxxopts/cxxopts.h"