Fix bazel BUILD file

Change-Id: Iff460cac58d2aedae038970f918ded5fb07e01d4

BUILD

diff --git a/BUILD b/BUILD
index 5530be2..45a2bbb 100644
--- a/BUILD
+++ b/BUILD
@@ -1,4 +1,4 @@
-load("//tools/bzl:plugin.bzl" "gerrit_plugin")
+load("//tools/bzl:plugin.bzl", "gerrit_plugin")
 
 gerrit_plugin(
     name = "zuul",