missing '#include <cstddef>' in format.h

[moiwi]

I get

fmt/format.h:3578:20: error: 'byte' is not a member of 'std'
 FMT_FORMAT_AS(std::byte, unsigned);

when compiling the current format.h.
I think

#include <cstddef>

is missing in format.h.

[vitaut]

Good catch, thanks. Fixed in 1f4a76d.