added lambda example for Neptune

Author: scmacdon

.doc_gen/metadata/cross_metadata.yaml

@@ -11,6 +11,7 @@ cross_Neptune_Query:
           block_content: cross_Neptune_Java_block.xml
   service_main: neptune
   services:
+    neptune:
     lambda:
 cross_MessageProcessingFrameworkTutorial:
   title: Use the &AWS; Message Processing Framework for .NET to publish and receive &SQS; messages