code: function populateLabelsForPR(pr) {
    print(['Get labels for PR ', clc.yellow.bold(`${pr.head.user.login}/${pr.head.repo.name}#${pr.number}`)], debug);
    return new Promise((resolve) => {
      github.issues.getIssueLabels({
        user: pr.base.user.login,
        repo: pr.base.repo.name,
        number: pr.number
      }, function (err, labels) {
        if (err && debug) {
          print(['Error fetching labels for PR ', clc.red.bold`${pr.base.user.login}/${pr.base.repo.name}#${pr.number}`], debug);
        }
        if (labels && labels.length > 0) {
          pr.labels = labels.map((label) => {
            return {
              name: label.name,
              color: label.color
            };
          });
        }
        return resolve(pr);
      });
    });
  }
docs: Fetch a list of labels for a single pull-request
  @param  {Object}  pr Pull-request metadata
  @return {Promise}    Resolves to an array of labels