Short answer, no—adding a cold air intake should not void your Ford warranty.
In general, no aftermarket modifications will completely void your warranty, regardless of what those modifications are or what kind of Ford you drive. However, the long answer is a bit more complicated than that.
But if your Ford ends up malfunctioning down the line, repairs may not be covered, if Ford can assert that the aftermarket cold air intake is to blame. Of course, this doesn’t apply to vehicle components that have nothing to do with the cold air intake. For example, if your power windows stop functioning, your warranty surely won’t be voided.