Update cut_to_disk.cpp

Former-commit-id: d974e22c6f2066633312148a3b1791643b7f6f0e

include/igl/cut_to_disk.cpp

@@ -1,4 +1,4 @@
-#include <igl/cut_to_disk.h>
+#include "cut_to_disk.h"
 
 #include <map>
 #include <set>