libconfig-dev for windows

[minkcv]

I noticed that a new library was added to be installed on linux. I think it is missing when I try to build on windows.

$ make texture.elf
Scanning dependencies of target cross2d
[  1%] Building CXX object libcross2d/CMakeFiles/cross2d.dir/source/skeleton/audio.cpp.obj
In file included from C:/Users/wsmith/libcross2d-examples/libcross2d/include/cross2d/c2d.h:23,
                 from C:/Users/wsmith/libcross2d-examples/libcross2d/source/skeleton/audio.cpp:7:
C:/Users/wsmith/libcross2d-examples/libcross2d/include/cross2d/skeleton/config.h:10:10: fatal error: libconfig.h: No such file or directory
   10 | #include <libconfig.h>
      |          ^~~~~~~~~~~~~
compilation terminated.
make[3]: *** [libcross2d/CMakeFiles/cross2d.dir/build.make:63: libcross2d/CMakeFiles/cross2d.dir/source/skeleton/audio.cpp.obj] Error 1
make[2]: *** [CMakeFiles/Makefile2:126: libcross2d/CMakeFiles/cross2d.dir/all] Error 2
make[1]: *** [CMakeFiles/Makefile2:322: examples/texture/CMakeFiles/texture.elf.dir/rule] Error 2
make: *** [Makefile:183: texture.elf] Error 2