Bazel: Add fixes for --incompatible_load_java_rules_from_bzl

Change-Id: I822955d5586174e8a0da83c0455b6e321ba44492

BUILD

diff --git a/BUILD b/BUILD
index 17789f5..f66fdd8 100644
--- a/BUILD
+++ b/BUILD
@@ -1,3 +1,4 @@
+load("@rules_java//java:defs.bzl", "java_library")
 load("//tools/bzl:junit.bzl", "junit_tests")
 load("//tools/bzl:plugin.bzl", "gerrit_plugin")