Upgrade metrics-graphite to 3.2.1

Change-Id: I788986b3d85921e1d8d45db7eb382112b4878568

external_plugin_deps.bzl

diff --git a/external_plugin_deps.bzl b/external_plugin_deps.bzl
index a9dd8a2..61e9951 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:3.1.2',
-    sha1 = '15a68399652c6123fe6e4c82ac4f0749e2eb6583',
+    artifact = 'io.dropwizard.metrics:metrics-graphite:3.2.1',
+    sha1 = '97b0457cab5ee94da3a946f6bb95053fac2181e2',
   )