patch 8.1.2415: popup menu flickers if an info popup is used

Problem:    Popup menu flickers if an info popup is used. (Nick Spoons)
Solution:   Set the pum_skip_redraw flag.
diff --git a/src/version.c b/src/version.c
index 4e9dc94..645631e 100644
--- a/src/version.c
+++ b/src/version.c
@@ -743,6 +743,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    2415,
+/**/
     2414,
 /**/
     2413,