(Starbucks) Big things are brewing at Starbucks.The coffee chain has announced plans to pay all U.S. employees a minimum wage of $15 over the next three years, expanding pay raises that begin next week.CEO Kevin Johnson shared the piping-hot news in a Wednesday memo, explaining that the chain will bump up in-store workers’ pay by at least 10% starting Monday, fast-tracking plans to pay everyone at least $15 an hour in the years to come.“We also recently shared one of our biggest wage investments of at least a 10 percent pay increase for our partners, all of whom already earn more than the minimum wage,” Johnson said, alluding to the November announcement. “With these investments, more than 30 percent of our U.S.