fmtlib: updated to 6.2.0

6.2.0:
* Improved error reporting when trying to format an object of a non-formattable type
* Reduced library size by ~10%.
* Always print decimal point if # is specified
* Implemented the 'L' specifier for locale-specific numeric formatting to improve compatibility with std::format. The 'n' specifier is now deprecated and will be removed in the next major release.
* Moved OS-specific APIs such as windows_error from fmt/format.h to fmt/os.h. You can define FMT_DEPRECATED_INCLUDE_OS to automatically include fmt/os.h from fmt/format.h for compatibility but this will be disabled in the next major release.
* Added precision overflow detection in floating-point formatting.
* Implemented detection of invalid use of fmt::arg.
* Used type_identity to block unnecessary template argument deduction.
* Improved UTF-8 handling
* Added experimental dynamic argument storage
* Made fmt::join accept initializer_list
* Fixed handling of empty tuples
* Fixed handling of output iterators in format_to_n
* Fixed formatting of std::chrono::duration types to wide output
* Added const begin and end overload to buffers
* Added the ability to disable floating-point formatting via FMT_USE_FLOAT, FMT_USE_DOUBLE and FMT_USE_LONG_DOUBLE macros for extremely memory-constrained embedded system
* Made FMT_STRING work with constexpr string_view
* Implemented a minor optimization in the format string parser
* Improved attribute detection
* Improved documentation
* Fixed symbol visibility on Linux when compiling with -fvisibility=hidden
* Implemented various build configuration fixes and improvements
* Fixed various warnings and compilation issues


(adam)