1.4.4

Features:

Custom named always null types in std::variant (@jbbjarnason):

struct named_always_null : std::monostate {};
template<>
glz::meta<named_always_null> { static constexpr std::string_view name{ "my name" };

std::variant<named_always_null, int, std::string> my_variant{};

Fixes:

• Arbitrary inputs are now rejected from integer reading. Integer parsing performance is also improved (@justend29)
• Added a missing fstream include to build (@justend29)
• clang + libstdc++ workaround for std::optional (@huangminghuang)