BUILD: Add dependency to commons-lang3

Previous change migrated the code to commons lang v3. The build
complains: "Using ...lang3.StringUtils from an indirect dependency".

Add commons-lang3 as dependency to the plugin in the BUILD.

Change-Id: I41af8f9cdba34d4995b545f3d282a2854d687c34
diff --git a/BUILD b/BUILD
index 1bcc32f..8a9da85 100644
--- a/BUILD
+++ b/BUILD
@@ -16,6 +16,7 @@
         "@istack-commons-runtime//jar",
         "@jaxb-api//jar",
         "@jaxb-runtime//jar",
+        "@commons-lang3//jar",
     ],
 )