Federal workplace safety regulators say an auto auction where five people died when a vehicle careened into a crowd last May has agreed to pay $200,000 in penalties.The U.S. Department of Labor’s Occupational Safety and Health Administration announced yesterday that Billerica-based LynnWay Auto Auction Inc. has also agreed to add several safety measures, including the installation of barriers in the auto auction area.In addition, an agency that supplied temporary employees to LynnWay has agreed to nearly $13,000 in penalties.