updated for version 7.3.1081

Problem:    Compiler warnings on 64-bit Windows.
Solution:   Change variable types. (Mike Williams)

src/if_py_both.h

@@ -1100,7 +1100,7 @@ typedef struct
     long_u	ht_used;
     hashtab_T	*ht;
     hashitem_T	*hi;
-    int		todo;
+    long_u	todo;
 } dictiterinfo_T;
 
     static PyObject *