patch 8.2.2153: popupwin test for latin1 still fails sometimes

Problem:    Popupwin test for latin1 still fails sometimes.
Solution:   Wait for the "cat" command to finish.
diff --git a/src/version.c b/src/version.c
index 3e64518..2bb336e 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    2153,
+/**/
     2152,
 /**/
     2151,