Work-around for nvcc

The nvcc compiler (at least up to 9.2) defines `__SIZEOF_INT128__`, but doesn't support 128-bit integers on device code:
```
error: "fmt::v6::format_arg_store<fmt::v6::basic_format_context<std::back_insert_iterator<fmt::v6::internal::buffer<char>>, char>, const char *, int, const char *>" contains a 128-bit integer, which is not supported in device code
```

include/fmt/core.h

@@ -266,7 +266,7 @@ template <typename T> struct std_string_view {};
 
 #ifdef FMT_USE_INT128
 // Do nothing.
-#elif defined(__SIZEOF_INT128__)
+#elif defined(__SIZEOF_INT128__) && !FMT_NVCC
 #  define FMT_USE_INT128 1
 using int128_t = __int128_t;
 using uint128_t = __uint128_t;