By Hannah Lang (Reuters) – A leading Senate Republican is urging the Biden administration to closely monitor the use of China’s recently launched digital currency during the Beijing Winter Olympics, where the country is expected to showcase the project to foreign visitors. In a letter sent Thursday to Treasury Secretary Janet Yellen and Secretary of State Antony Blinken, Senator Pat Toomey expressed concern that the Chinese government could use the global event to help its digital yuan, dubbed e-CNY, gain a global foothold. Such an effort could be used to set standards in cross-border payments…