add 'SearchHistory' to init

Author: SimonBlanke

src/hyperactive/base/__init__.py

@@ -2,6 +2,7 @@
 # copyright: hyperactive developers, MIT License (see LICENSE file)
 
 from hyperactive.base._experiment import BaseExperiment
+from hyperactive.base._history import SearchHistory
 from hyperactive.base._optimizer import BaseOptimizer
 
-__all__ = ["BaseExperiment", "BaseOptimizer"]
+__all__ = ["BaseExperiment", "BaseOptimizer", "SearchHistory"]