Bazel: Consider setting timeout="short" or size="small"

Fix Bazel warning.

Change-Id: If7372bf1e67f567cc2131c0f697180e7e93a3238
diff --git a/BUILD b/BUILD
index 24a147e..17ab6b3 100644
--- a/BUILD
+++ b/BUILD
@@ -19,6 +19,7 @@
 
 junit_tests(
     name = "reviewers_tests",
+    size = "small",
     srcs = glob(["src/test/java/**/*.java"]),
     tags = ["reviewers"],
     deps = [