public function createMilestone(string $title, string $state = AbstractApi::STATE_OPEN, string $description = '',
                                    string $dueOn = ''): array
    {
        return $this->getApi()->request($this->getApi()
                                             ->sprintf('/repos/:owner/:repo/milestones', $this->getIssues()->getOwner(),
                                                 $this->getIssues()->getRepo()), Request::METHOD_POST, [
                'title'       => $title,
                'state'       => $state,
                'description' => $description,
                'due_on'      => (new DateTime($dueOn))->format(DateTime::ATOM)
            ]);
    }