The notification spec is being updated to rename "phase" to "status" and make
it a required field. This updates the notification base code and docs to
reflect this modification. Version for the notification EventType base class is
also bumped.
Change-Id: I11b6ea44a01d2a830b592784ccc63a1de9bf2ec1
Depends-On: Ib25bd5a3a600c13f7b265d86ad253af3dfa5552f