Add Missing Event Types (#1536)

* Adding missing review types to event info.

* Fixing whitespace.

* Reword `BaseRefChanged` comment

Octokit/Models/Response/EventInfo.cs

@@ -178,6 +178,26 @@ namespace Octokit
         /// </summary>
         Committed,
 
+        /// <summary>
+        /// The actor requested review from the subject on this pull request.
+        /// </summary>
+        ReviewRequested,
+
+        /// <summary>
+        /// The actor dismissed a review from the pull request.
+        /// </summary>
+        ReviewDismissed,
+
+        /// <summary>
+        /// The actor removed the review request for the subject on this pull request.
+        /// </summary>
+        ReviewRequestRemoved,
+
+        /// <summary>
+        /// Base branch of the pull request was changed.
+        /// </summary>
+        BaseRefChanged,
+
         /// <summary>
         /// The issue was referenced from another issue.
         /// The source attribute contains the id, actor, and
@@ -186,4 +206,4 @@ namespace Octokit
         [SuppressMessage("Microsoft.Naming", "CA1704:IdentifiersShouldBeSpelledCorrectly", MessageId = "Crossreferenced")]
         Crossreferenced
     }
-}
+}