Exactly requires c++17 and higher

[b6675]

There is marked with cpp14, but project requires cpp17 at least
scoped_lock, template<auto N, ...>
if constexpr, std::apply do not let downscale requirements
msvc 19 at least c++17
gcc 12 at least c++20 with warning meantioned #8 (comment)
clang 15 at least c++20