Update FBXBinaryTokenizer.cpp

- closes https://github.com/assimp/assimp/issues/5072

code/AssetLib/FBX/FBXBinaryTokenizer.cpp

@@ -51,6 +51,7 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #include "FBXUtil.h"
 #include <assimp/defs.h>
 #include <stdint.h>
+#include <cstdint>
 #include <assimp/Exceptional.h>
 #include <assimp/ByteSwapper.h>
 #include <assimp/DefaultLogger.hpp>