2.2.0

Major changes:

• Field names reflection. Added new constexpr pfr::get_name<N, T>() function that returns a std::string_view with a name of field at index N of an aggregate T. Requires C++20. PFR_CORE_NAME_ENABLED is defined to 1 if the functionality is available. Many thanks to Denis Mikhailov, Bela Schaum and X-Ryl669 for the PR PR#129 and implementation ideas.

• for_each_field() is now constexpr for C++17. Many thanks to Alexander Karatarakis for the PR PR#134.