Update for repo best practices (dart-lang/clock#14)

- Use `pub.dev` links over `dardocs.org`.
- In example, follow `package:pedantic` style for function typed
  argument.
- Drop unused author field from pubspec.
- Use a simpler constraint on `package:meta` since the SDK constraint
  already prevents us from picking up older versions.
4 files changed
tree: eaf26e0f0ca1a2c2a2ecfce3786095aa464f08ce
  1. pkgs/