With big days from Mike Yastrzemski and Joc Pederson and an immaculate effort from their bullpen, the Giants beat the Rockies, 3-0, on Thursday, to complete their first four-game sweep of the season. The Giants’ combined shutout — using six pitchers in their second bullpen game of the series — was their first at Coors Field since 2012 and their fifth time blanking the home team since the mile-high ballpark opened in 1997. Here are some takeaways. Thunder and lightning: Yastrzemski and Pederson teamed up to produce the Giants’ first two runs and turned in a pair of multi-hit efforts — while pro…