patch 9.0.0728: extend() test fails

Problem:    extend() test fails.
Solution:   Item is final, not const.
diff --git a/src/version.c b/src/version.c
index ec74f52..0a8eb00 100644
--- a/src/version.c
+++ b/src/version.c
@@ -700,6 +700,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    728,
+/**/
     727,
 /**/
     726,