patch 8.1.2329: mouse multiple click test is a bit flaky

Problem:    Mouse multiple click test is a bit flaky.
Solution:   Add it to the list of flaky tests.
diff --git a/src/version.c b/src/version.c
index 2469ce9..76e3f1b 100644
--- a/src/version.c
+++ b/src/version.c
@@ -738,6 +738,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    2329,
+/**/
     2328,
 /**/
     2327,