Use EventGsonProvider from Gerrit core

EventGsonProvider was moved to Gerrit Core and removed from
events-broker library.

Bug: Issue 14438
Change-Id: Ice8b50faf5f5521fbc92a0661b614ef8a2e78fe0

external_plugin_deps.bzl

diff --git a/external_plugin_deps.bzl b/external_plugin_deps.bzl
index 0833f02..93ddd9e 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:3.4.0.1",
-        sha1 = "2d406afa8787621442d855e4b458c97bd24f1198",
+        artifact = "com.gerritforge:events-broker:3.4.0.2",
+        sha1 = "8a56300ce92c3e25b4669a0511b4c520b34851b2",
     )

src/test/java/com/googlesource/gerrit/plugins/multisite/index/GroupEventIndexTest.java

diff --git a/src/test/java/com/googlesource/gerrit/plugins/multisite/index/GroupEventIndexTest.java b/src/test/java/com/googlesource/gerrit/plugins/multisite/index/GroupEventIndexTest.java
index 93cec05..77d00ac 100644
--- a/src/test/java/com/googlesource/gerrit/plugins/multisite/index/GroupEventIndexTest.java
+++ b/src/test/java/com/googlesource/gerrit/plugins/multisite/index/GroupEventIndexTest.java
@@ -16,7 +16,7 @@
 
 import static com.google.common.truth.Truth.assertThat;
 
-import com.gerritforge.gerrit.eventbroker.EventGsonProvider;
+import com.google.gerrit.server.events.EventGsonProvider;
 import com.google.gson.Gson;
 import com.googlesource.gerrit.plugins.multisite.forwarder.events.GroupIndexEvent;
 import java.util.UUID;