Banks and credit unions united Wednesday to squash a bill that would have limited credit-card transaction fees they can impose on Colorado businesses. State Reps. Jon Becker, R-Fort Morgan, and Alec Garnett, D-Denver, had put forward the idea that the Legislature become the first in the country to prohibit financial institutions from charging transaction fees on the portion of electronic payment transactions that cover local taxes. When they received an avalanche of opposition from banks, credit…