fix case sensitive #include for windows opengl3.3#379

Moros1138 wants to merge 1 commit intodevelopOneLoneCoder/olcPixelGameEngine:developfrom

case-sensitivity-strikes-again!-fix-cross-compiling-mingw-on-linuxOneLoneCoder/olcPixelGameEngine:case-sensitivity-strikes-again!-fix-cross-compiling-mingw-on-linuxCopy head branch name to clipboard