Changed version constraint on analyzer because 0.23.0 has breaking changes
Changed version constraint on analyzer because 0.23.0 has breaking changes

Review URL: https://codereview.chromium.org/1002683002

google/reflectable.dart,jakemac53/reflectable,jakemac53/reflectable,luisvt/reflectable,luisvt/reflectable,google/reflectable.dart,bwu-dart-contributing/reflectable,bwu-dart-contributing/reflectable