WASHINGTON, July 28 (Reuters) - The United States unveiled a Taiwan weapons aid package worth up to $345 million on Friday, a move likely to anger China even as the Biden administration declined to publicly provide details on the arms in the package. Foreshadowing the upcoming aid, Secretary of Defense Lloyd Austin on May 16 told a Senate panel: "I'm pleased that the United States will soon provide significant additional security assistance to Taiwan through the Presidential Drawdown Authority that Congress authorized last year. The Taiwan PDA, however, is a non-emergency authority approved by Congress last year