Bump up globabl-refdb to 3.6.3.4

Change-Id: I68bf42cad3c8a76b1f385487274abc29c1709f9e
diff --git a/external_plugin_deps.bzl b/external_plugin_deps.bzl
index 597ee1f..e989875 100644
--- a/external_plugin_deps.bzl
+++ b/external_plugin_deps.bzl
@@ -3,8 +3,8 @@
 def external_plugin_deps():
     maven_jar(
         name = "global-refdb",
-        artifact = "com.gerritforge:global-refdb:3.6.3.3",
-        sha1 = "c6286e75b630283738320906ba1b020fc399f13d",
+        artifact = "com.gerritforge:global-refdb:3.6.3.4",
+        sha1 = "1bd96a9f80b35e24a9b17becb0f49a510758a2fa",
     )
 
     maven_jar(