patch 8.2.0475: channel out_cb test still fails sometimes on Mac

Problem:    Channel out_cb test still fails sometimes on Mac.
Solution:   Use an ever longer timeout.
diff --git a/src/version.c b/src/version.c
index d06b4b7..69afadf 100644
--- a/src/version.c
+++ b/src/version.c
@@ -739,6 +739,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    475,
+/**/
     474,
 /**/
     473,