patch 8.2.1220: memory access error when dragging a popup window

Problem:    memory access error when dragging a popup window over a buffer
            with folding.
Solution:   Avoid going over the end of the cache. (closes #6438)

src/version.c

@@ -754,6 +754,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1220,
 /**/
     1219,
 /**/