Format BUILD file with buildifier 0.12.0

Change-Id: I2bbd74736f2e62380d724f44b6b26dd5ef8af24b

BUILD

diff --git a/BUILD b/BUILD
index cc18db3..69517a9 100644
--- a/BUILD
+++ b/BUILD
@@ -1,5 +1,5 @@
 load("//tools/bzl:junit.bzl", "junit_tests")
-load("//tools/bzl:plugin.bzl", "gerrit_plugin", "PLUGIN_DEPS", "PLUGIN_TEST_DEPS")
+load("//tools/bzl:plugin.bzl", "PLUGIN_DEPS", "PLUGIN_TEST_DEPS", "gerrit_plugin")
 
 gerrit_plugin(
     name = "automerger",