NEW YORK — Coinbase has been targeted by U.S. regulators in a new lawsuit Tuesday that alleges the cryptocurrency platform is operating as an unregistered securities platform and brokerage service.The lawsuit from the Securities and Exchange Commission comes only a day after it filed charges against Binance, the world’s largest crypto exchange, and its founder Changpeng Zhao are accused of misusing investor funds, operating as an unregistered exchange and violating a slew of U.S. securities laws.Coinbase shares …