Updates the current versions of pyenv and python-Build

    CLI Example:

    .. code-block:: bash

        salt '*' pyenv.update

def update(runas=None, path=None):
    '''
    Updates the current versions of pyenv and python-Build

    CLI Example:

    .. code-block:: bash

        salt '*' pyenv.update
    '''
    path = path or _pyenv_path(runas)
    path = os.path.expanduser(path)

    return _update_pyenv(path, runas)