Update libfmt to 11.2.0

[henri-gasc]

As stated in the libfmt release note:
Deprecated fmt::localtime in favor of std::localtime.

This also fixes part of WerWolv/ImHex#2225

[WerWolv]

Thank you! Is fmt::gmtime affected as well? Kinda weird that they'd only deprecate one and not the other

[henri-gasc]

From what I can see, it is not impacted.
They probably deprecated localtime and not gmtime, because the latter is not thread-safe in std (as in, This function may not be thread-safe. as opposed to This function may not be thread-safe. The [Microsoft CRT](https://learn.microsoft.com/en-us/cpp/c-runtime-library/reference/localtime-localtime32-localtime64) implementation is thread-safe., but yeah, kinda weird

[WerWolv]

Well we're using libstdc++, not MSVC so who knows if it is in our case. I just went ahead and replaced gmtime as well just for consistency. (Also fixed the build issue due to the different interface)