Upgrade metrics-graphite to 4.0.3

To align with the version of metrics-core used in core Gerrit
since 2.14.11.

Change-Id: I352f5c413579593b9af1d61152be93d1c89383c6

external_plugin_deps.bzl

diff --git a/external_plugin_deps.bzl b/external_plugin_deps.bzl
index 9325ea1..1cb5b8b 100644
--- a/external_plugin_deps.bzl
+++ b/external_plugin_deps.bzl
@@ -3,6 +3,6 @@
 def external_plugin_deps():
     maven_jar(
         name = "metrics_graphite",
-        artifact = "io.dropwizard.metrics:metrics-graphite:4.0.2",
-        sha1 = "c58939a16560d60d3f3d7fe941d2dc9f41ba3b6c",
+        artifact = "io.dropwizard.metrics:metrics-graphite:4.0.3",
+        sha1 = "557cb9adbd442852e12f8f41ddb81a889f670139",
     )