Update a record.

    Arguments:

        prs:  parser object of argparse
        conn: dictionary of connection information

def parse_update(prs, conn):
    """Update a record.

    Arguments:

        prs:  parser object of argparse
        conn: dictionary of connection information
    """

    prs_update = prs.add_parser(
        'update', help='update record of specific zone')
    set_option(prs_update, 'domain')
    set_option(prs_update, 'update')
    conn_options(prs_update, conn)
    prs_update.set_defaults(func=update)