SHANGHAI, Sept 6 (Reuters) - China lifted its official yuan midpoint to an over 2-1/2-month high on Monday to reflect broad weakness in the dollar. The People’s Bank of China (PBOC) set the midpoint at 6.4529 yuan per dollar prior to the market open, 48 pips or 0.07%, stronger than the previous fix of 6.4577. The dollar languished near a one-month low versus major peers, as investors pushed back expectations for when the Federal Reserve will begin tapering its massive stimulus.