What's Changed
* Add state filters in TrialList by c-bata in https://github.com/optuna/optuna-dashboard/pull/363
* Hide user_attrs on GraphParallelCoordinate by default by c-bata in https://github.com/optuna/optuna-dashboard/pull/365
* Update `TrialList` component by c-bata in https://github.com/optuna/optuna-dashboard/pull/364
* Support user attributes on GraphSlice by c-bata in https://github.com/optuna/optuna-dashboard/pull/366
* Remove TODOs in CachedExtraStudyProperty by c-bata in https://github.com/optuna/optuna-dashboard/pull/367
* Set `key` attributes in `TrialList` by c-bata in https://github.com/optuna/optuna-dashboard/pull/368
* Avoid to calculate importance when only available single trial by c-bata in https://github.com/optuna/optuna-dashboard/pull/369
* Add trial tell feature by keisuke-umezawa in https://github.com/optuna/optuna-dashboard/pull/355
* Introduce `Artifact` by c-bata in https://github.com/optuna/optuna-dashboard/pull/314
* Introducing Custom User Widget by c-bata in https://github.com/optuna/optuna-dashboard/pull/370
* Save reload interval on localStorage by c-bata in https://github.com/optuna/optuna-dashboard/pull/372
* Bump the version up to v0.9.0b3 by c-bata in https://github.com/optuna/optuna-dashboard/pull/373
**Full Changelog**: https://github.com/optuna/optuna-dashboard/compare/v0.9.0b2...v0.9.0b3