dateLastPublished on JobOrder isn't available through the SDK

[SimonOkeeffe]

dateLastPublished on JobOrder is available through metadata/to be searched upon, but not available on the SDK to pull.

http://bullhorn.github.io/rest-api-docs/entityref.html#joborder

This would benefit cube19 as we have a client who wants to monitor when Jobs are published and which Jobs are published. Though there is a "Publishing Status" field available so we know a Job has been published, knowing when it happens is key for the metrics the client wants to report over.