Pepsi is hoping to win back soda drinkers with a compromise. Some people don’t like the calories in regular soda, but loathe the taste of zero-calorie diet drinks. So the nation’s No. 2 cola company is rolling out “Pepsi Next,’’ a cola that has about half the calories of regular Pepsi at 60 calories per can. The cola, which is slated to hit store shelves nationally by the end of March, is Pepsi’s biggest product launch in years. The drink comes as people increasingly move away from sugary drinks to water and other lower-calorie beverages because of health concerns. It’s also an attempt by Pepsi to revive the cola wars against Coke and others.