CHICAGO — Kyle Hendricks wanted to set the tone with his opening-day start. Coming off a career-worst season, Hendricks expressed during spring training how he has a lot to prove to himself this year. The veteran delivered a vintage performance in his season debut. Armed with a changeup that constantly fooled Milwaukee’s hitters, Hendricks exited with the lead after 5 ⅓ innings, striking out seven, walking three and allowing only one run. The Cubs did enough against reigning Cy Young winner Corbin Burnes and Milwaukee’s bullpen to pull out a 5-4 opening-day win. David Robertson earned the save…