buildbucket.config: hide retry button

The "retry all builds" button is misleading for the Go project.
The main issue is that even if all builds succeed again, it will not
update the LUCI-Trybots-Result+1 label because that's only mutated by
CV. The buildbucket plugin does not talk to CV. Hide it. Developers
should just hit Commit-Queue+1 again.

Change-Id: Ia7f38c3d171661384cf10f496d46cebf69068807
Reviewed-on: https://go-review.googlesource.com/c/All-Projects/+/559740
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>

buildbucket.config

diff --git a/buildbucket.config b/buildbucket.config
index 0af87d8..20c6f8f 100644
--- a/buildbucket.config
+++ b/buildbucket.config
@@ -3,3 +3,6 @@
 	gerrit = "go-review.googlesource.com"
 
 [bucket "luci.golang.try"]
+
+[option]
+	hide-retry-button = true