Update package to pedantic 1.8.0 (dart-lang/clock#12)

* Update package to pedantic 1.8.0

* Update travis to use stable, update SDK constraints

* format files

* Travis: test with 2.1.1
12 files changed
tree: 725d2936a75740a841d9820e1fc4f287c45f340f
  1. pkgs/