“Summerfest” taps a few West Coast veterans and a Martian. Hip-hop fans can take solace in a new development: this year, Milwaukee’s “Summerfest” has their best interests at heart. The “world’s largest music festival” has officially announced some of its attendees, which includes a jam-packed Sunday of ScHoolboy Q, Snoop Dogg, and Lil Wayne. The acclaimed trifecta will officially bring the festival to …