Use unique library names (dart-lang/package_config#107)

The current dartdocs output does not link correctly because of the
conflicting library names.

- Use a stable SDK and dependencies.
- Test on the oldest supported SDK.
- Remove dependency overrides.
4 files changed
tree: 2691f38cc643f7ad8feae58a3f5615fbd51bff03
  1. pkgs/