createReview method

Creates a new pull request comment.

API docs: https://developer.github.com/v3/pulls/comments/#create-a-comment

Implementation

Future<PullRequestReview> createReview(
    RepositorySlug slug, CreatePullRequestReview review) {
  return github.postJSON(
          '/repos/${slug.fullName}/pulls/${review.pullNumber}/reviews',
          body: GitHubJson.encode(review),
          convert: (dynamic i) => PullRequestReview.fromJson(i))
      as Future<PullRequestReview>;
}