Sort headers in SDL_gpu.h

include/SDL3/SDL_gpu.h

@@ -31,8 +31,8 @@
 #define SDL_GPU_H
 
 #include <SDL3/SDL_stdinc.h>
-#include <SDL3/SDL_properties.h>
 #include <SDL3/SDL_pixels.h>
+#include <SDL3/SDL_properties.h>
 #include <SDL3/SDL_rect.h>
 #include <SDL3/SDL_surface.h>
 #include <SDL3/SDL_video.h>