Upgrade groovy-all to version 2.4.12

Change-Id: I2672ff3ade613e174d444978548a76b831cb05a5

external_plugin_deps.bzl

diff --git a/external_plugin_deps.bzl b/external_plugin_deps.bzl
index c2e6049..a861ca5 100644
--- a/external_plugin_deps.bzl
+++ b/external_plugin_deps.bzl
@@ -3,6 +3,6 @@
 def external_plugin_deps():
   maven_jar(
     name = 'groovy',
-    artifact = 'org.codehaus.groovy:groovy-all:2.2.1',
-    sha1 = '07ae565d50d24167c4e5d74b96f4126d4c56f16f',
+    artifact = 'org.codehaus.groovy:groovy-all:2.4.12',
+    sha1 = '760afc568cbd94c09d78f801ce51aed1326710af',
   )