updated for version 7.2.421

Problem:    Folds are sometimes not updated properly and there is no way to
            force an update.
Solution:   Make "zx" and "zX" recompute folds (suggested by Christian
            Brabandt)

src/version.c

@@ -681,6 +681,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    421,
 /**/
     420,
 /**/