patch 9.0.0596: CI on Mac M1 has the channel feature disabled

Problem:    CI on Mac M1 has the channel feature disabled.
Solution:   Include the channel feature.
diff --git a/src/version.c b/src/version.c
index 35f37e9..3111b4f 100644
--- a/src/version.c
+++ b/src/version.c
@@ -700,6 +700,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    596,
+/**/
     595,
 /**/
     594,