Add trigger capability on github pr review

A github pull request review is a new type of event that happens when
user provides a review of a pull request
https://developer.github.com/v3/pulls/reviews

It will create an event
https://developer.github.com/v3/activity/events/types/#pullrequestreviewevent
sent to the webhook. Allow filtering on submitted or dismissed actions
and the state of the review of approved, comment, or request_changes.

Signed-off-by: Jesse Keating <omgjlk@us.ibm.com>
Change-Id: If94c2fe8adbe18fa7f426d5462559ba24963424c
7 files changed