Fix an include error

Boscuit · Boscuit · commit 2c741eb0056f · 2020-08-14T12:02:40.000+08:00
diff --git a/src/iou.cpp b/src/iou.cpp
@@ -10,7 +10,7 @@
  * 2018
  ***********************************/
 
-#include "IOU.h"
+#include "iou.h"
 #include <algorithm>
 
 namespace IOU
