WASHINGTON (Reuters) -The U.S. State Department has approved a $300 million sale of equipment to help maintain Taiwan’s tactical information systems, the Pentagon said on Friday, the latest U.S. assistance for the island’s defenses. The United States is bound by law to provide Chinese-claimed Taiwan with the means to defend itself and arms sales are a frequent source of tension between Washington and Beijing. The Pentagon’s Defense Security Cooperation Agency said the sale was for follow-on life cycle support to maintain Taiwan’s Command, Control, Communications, and Computers, or C4, capabili…