Bump events-broker to 3.4.0-rc0

Change-Id: I0b98f3769434df898b916e3d3fcbd960c2f7491c
diff --git a/external_plugin_deps.bzl b/external_plugin_deps.bzl
index 82cd5e8..fc1b8ad 100644
--- a/external_plugin_deps.bzl
+++ b/external_plugin_deps.bzl
@@ -9,6 +9,6 @@
 
     maven_jar(
         name = "events-broker",
-        artifact = "com.gerritforge:events-broker:3.3.1",
-        sha1 = "90775e671946b20e52be3a11277d1ed33973d66e",
+        artifact = "com.gerritforge:events-broker:3.4.0-rc0",
+        sha1 = "8c34c88103d4783eb4c4decde6d93541bc1cf064",
     )