adaptor → cpp17 Relation

File in msgpack/adaptor	Includes file in msgpack/v1/adaptor/cpp17
cpp17 / byte.hpp	byte.hpp
cpp17 / carray_byte.hpp	carray_byte.hpp
cpp17 / optional.hpp	optional.hpp
cpp17 / string_view.hpp	string_view.hpp
cpp17 / vector_byte.hpp	vector_byte.hpp