Implement Review API for Pull Requests (#1648)

* First Iteration Need to finish tests and docs

* Mostly Complete

* Fixing tests and adding review comments

* Added tests for reactive client

* Moved Reviews inside fo the Pull request client for better organization and began initial intigration testing

* Fixing bad recursive function breaking tests

* test fixes

* Add paging support to review comments call

* Fixing recursive function

* Addressing comments from PR

* fixing CI break

* Typo build break

* Fixing Convention Tests

* Adding correct nameof() usage in Ensure

* Small consitancy changes

* Trigger build

* Address PR Comments

* Fixup test naming

* Fix sub client ordering and incorrect URL

* Tidy up comments and remove StringEnum wrapper from Request models as it is only for Response models

* Rename GetReview to Get

* tweak debugger display

* Rework integration tests - implement the easy Get/GetAll ones first...

* Implement integration tests for Create method.
Move helpers to create PR/review into SetupHelper class
Fixed up review status enum to contain correct values
Tests for Approve/RequestChanges currently failing as a user cant approve/request changes on their own PR

* Implement secondary account settings for integration tests and a new [DualAccountTest] attribute for discovery when configured
Change integration test to create PR from the 2nd account, so the main test account is able to perform review actions on the PR

* Add integration tests for Delete, Dismiss and Submit methods
Fixed up API client implementation for delete (was looking for incorrect 201 http status)
Removed unnecessary await/async calls from client implementations that dont need to do anything with the result

* Attempting to add comments as part of a review revealed that we cant use the existing PullRequestReviewCommentCreate class as the API throws a validation error due to the CommitId field
These newer review APIs need a DraftPullRequestReviewComment (that doesnt have a commitId) instead

* add second test account user/password to configure-integration-tests script

Octokit.Reactive/Clients/IObservablePullRequestsClient.cs

@@ -17,6 +17,11 @@ namespace Octokit.Reactive
         [Obsolete("Please use IObservablePullRequestsClient.ReviewComment. This will be removed in a future version")]
         IObservablePullRequestReviewCommentsClient Comment { get; }
 
+        /// <summary>
+        /// Client for managing reviews.
+        /// </summary>
+        IObservablePullRequestReviewsClient Review { get; }
+       
         /// <summary>
         /// Client for managing review comments.
         /// </summary>