If in fact it is the "spring" squeaking, there is a good chance it is broken. If not there is likely a build up of dirt/gravel in the lower pocket. Clean it out and see if that helps. I would be more inclined to think the squeak is from the control arm bushings, or the sway bar bushings. You could remove the sway bar temporarily to check it. If that is the noise, clean it and relube with a quality rubber lube. If its the control arm, or possably the ball joint pieces will need replaced.
When I installed my new springs I didn't put the rubber bushings back on the top and bottom of the springs, it squeaks like hell. Mine were completely worn out and I don't ming noisy cars. Hanvn't had a problems, just noits. I'd bet money that's what it is. Bushings are cheap so is taking out the spring. You'll need an alignment when you put it back together.