The Oakland Comedy Festival returns this weekend for its sixth year, featuring dozens of up-and-coming and established talent. Mike E. Winfield, a comic who has been featured on “America’s Got Talent” and “The Late Show with Stephen Colbert,” will headline the event Sunday.  Shoshanna Howard, Oakland Comedy Festival host and founder, said the event is all about bringing people together. With Bay Area comedy venues like Alameda Comedy Club, Cal Shakes, and San Francisco’s Milk Bar shutting down, Howard said…