patch 8.1.1418: win_execute() is not implemented yet

Problem:    Win_execute() is not implemented yet.
Solution:   Implement it.
diff --git a/src/version.c b/src/version.c
index 38b51f7..511b28b 100644
--- a/src/version.c
+++ b/src/version.c
@@ -768,6 +768,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1418,
+/**/
     1417,
 /**/
     1416,