patch 8.0.0582: illegal memory access with z= command

Problem:    Illegal memory access with z= command. (Dominique Pelle)
Solution:   Avoid case folded text to be longer than the original text.  Use
            MB_PTR2LEN() instead of MB_BYTE2LEN().

src/version.c

@@ -764,6 +764,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    582,
 /**/
     581,
 /**/