What's Changed
* Follow PEP 561 – Distributing and Packaging Type Information by xadrianzetx in https://github.com/xadrianzetx/optuna-distributed/pull/84
* Bump version to `0.6.1` by xadrianzetx in https://github.com/xadrianzetx/optuna-distributed/pull/85
**Full Changelog**: https://github.com/xadrianzetx/optuna-distributed/compare/v0.6.0...v0.6.1