Private equity firm Main Post Partners has made an investment in color cosmetics brand Milk Makeup. The minority investment is the first outside capital for Milk and will help management accelerate Milk’s path toward becoming a leading global brand.   For more than 20 years, Milk has been at the cultural intersection of the fashion, music photography and film worlds and is a hub for nurturing creativity. In 2016, Milk launched its first consumer product line, Milk Makeup, which has rapidly gro...