It is either a loose hub bearing assembly or you are seeing the early signs of a caliper piston stuck and causing pad rub. If at any point the squeak turns into a chugging/rumble, look at your rotor and see if it has any grooves in it. If so, it is a stuck caliper piston. Either way, I honestly believe it is a bearing assembly that needs to be tightened up. I say that because my Regal did the same thing. It squeaked from the left front for the longest time, but the brakes were new. My mechanic rode with me one day and said that he was confident it was a bad bearing. Then he looked at it and told me it was. Good luck. Either way, brake or hub, they are easy to fix right now, but I would suggest getting it checked out soon because if it is in fact a caliper piston stuck, you could end up grooving out your rotor and burning your pads out. A new rotor, pads, and caliper are not exactly cheap. Good luck.
