New Features:
* tune-sklearn now supports sampling with Optuna! (136, 132)
* You can now do deadline-based hyperparameter tuning with the new `time_budget_s` parameter (134)
* Custom logging can be done by passing in loggers as strings (`TuneSearchCV(loggers=["json", "tensorboard"])`) (100)
* Reproducible experiments can be set with a `seed` parameter to make initial configuration sampling deterministic (140)
* Custom stopping (such as stopping a hyperparameter search upon plateau) is now supported (156)
Improvements:
* Support for Tune search spaces (128)
* Use fractional GPUs for a Ray cluster (145)
* Bring API in line with sklearn `best_params` accessible without `refit=True`, (114)
* Early stopping support for sklearn Pipelines, LightGBM and CatBoost (103, 109)
* Implement resource step for early stopping (121)
* Raise Errors on trial failures instead of logging them (130)
* Remove unnecessary dependencies (152)
Bug fixes:
* Refactor early stopping case handling in `_train` (97)
* Fix Warm start errors (106)
* Fix hyperopt loguniform params (104)
* Fix of multi_metric scoring issue (111)
* BOHB sanity checks (133)
* Avoid Loky Pickle Error (150)
Special thanks to: krfricke, amogkam, Yard1, richardliaw, inventormc, mattKretschmer