Retrieves the release notes, from the RELEASE_NOTES file (if in a package)
    or generates it from the git history.

    Args:
        project_dir(str): Path to the git repo of the project.
        bugtracker_url(str): Url to the bug tracker for the issues.

    Returns:
        str: release notes

    Raises:
        RuntimeError: If the release notes could not be retrieved

def get_releasenotes(project_dir=os.curdir, bugtracker_url=''):
    """
    Retrieves the release notes, from the RELEASE_NOTES file (if in a package)
    or generates it from the git history.

    Args:
        project_dir(str): Path to the git repo of the project.
        bugtracker_url(str): Url to the bug tracker for the issues.

    Returns:
        str: release notes

    Raises:
        RuntimeError: If the release notes could not be retrieved
    """
    releasenotes = ''
    pkg_info_file = os.path.join(project_dir, 'PKG-INFO')
    releasenotes_file = os.path.join(project_dir, 'RELEASE_NOTES')
    if os.path.exists(pkg_info_file) and os.path.exists(releasenotes_file):
        with open(releasenotes_file) as releasenotes_fd:
            releasenotes = releasenotes_fd.read()

    else:
        releasenotes = api.get_releasenotes(
            repo_path=project_dir,
            bugtracker_url=bugtracker_url,
        )

    return releasenotes