Update OpenColorIO.h (#2020)

Fix for building with gcc-15

Signed-off-by: Mahesh Madhav <[email protected]>
Co-authored-by: Doug Walker <[email protected]>

Author: heshpdx

include/OpenColorIO/OpenColorIO.h

@@ -12,6 +12,7 @@
 #include <string>
 #include <fstream>
 #include <vector>
+#include <cstdint>
 
 #include "OpenColorABI.h"
 #include "OpenColorTypes.h"