Refactor away from deprecated error (dart-lang/pub_semver#72)

* Refactor away from deprecated error

`FallThroughError` is deprecated, and scheduled for removal in 3.0

* Update version_constraint.dart
1 file changed
tree: 8802f3aa2ef2f307cc5b456d13136c4d5ef4ea4f
  1. pkgs/