Adapt to bazel 9.1.0 update

Change-Id: I31bffda535efb37cfda58c535e0c898015e908b2

BUILD

diff --git a/BUILD b/BUILD
index effccb5..250b018 100644
--- a/BUILD
+++ b/BUILD
@@ -15,6 +15,7 @@
     "@com_googlesource_gerrit_bazlets//tools:runtime_jars_overlap.bzl",
     "runtime_jars_overlap_test",
 )
+load("@rules_java//java:defs.bzl", "java_library")
 
 gerrit_plugin(
     name = "spanner-refdb",