main: use lowercase windows header include
main: use lowercase windows header include

By default MinGW on GNU/Linux use lower case headers and on case-sensitive file-systems the header won't be found.
So lower-casing this import will solve that issue while not impacting Windows.
maximd33/mfx_dispatch,lu-zero/mfx_dispatch,lu-zero/mfx_dispatch,maximd33/mfx_dispatch