Does not build under VC++ 2022 with newest updates

[luz-arreola]

          The current version of Bustache builds just fine under **VC++ 2022 update 17.1.6** but if you install update **17.10.0** or **17.12.0** (the very latest update) you get   an error:

C:\bustache-master\include\bustache\model.hpp(353,19): error C2248: 'std::basic_format_context<bustache::detail::print_fmt::OutIter,char>::basic_format_context': cannot access private member declared in class 'std::basic_format_context<bustache::detail::print_fmt::OutIter,char>'

Thank you.

Originally posted by @luz-arreola in #34 (comment)

[luz-arreola]

I changed the compiler used in VC++ 2022 to clang and get a smiliar error:

C:\bustache-master\include\bustache/model.hpp(353,16): error : calling a private constructor of class 'std::basic_format_context<std::back_insert_iterator<bustache::detail::output_buffer>, char>'