bump rubocop to 0.42.0
bump rubocop to 0.42.0

jvoss/thredded,jvoss/thredded,jvoss/thredded,jayroh/thredded,jvoss/thredded,jayroh/thredded,jayroh/thredded,jayroh/thredded,thredded/thredded,thredded/thredded,thredded/thredded,thredded/thredded