Breaking Change for KB Portlet

Hey Jim,

You probably saw Brian's ticket in regards to updating a new *Breaking Changes* document based on the KB portlet. I went ahead and edited the latest breaking change and am sending my edits in this PR. I'll keep an eye on this document and edit accordingly, as we do with the original Liferay Portal 7.0 document. Thanks.

https://issues.liferay.com/browse/LRDOCS-1289