patch 9.0.1536: CI: sound dummy stopped working

Problem:    CI: sound dummy stopped working.
Solution:   Temporarily stop using sound dummy.
diff --git a/src/version.c b/src/version.c
index 8da355b..c8daf71 100644
--- a/src/version.c
+++ b/src/version.c
@@ -696,6 +696,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1536,
+/**/
     1535,
 /**/
     1534,