[Feature Request] Ability to use the validation_split configuration during the KerasMember construction

[talhakabakus]

As the title clearly describes the feature request I'm making, I think it'd be really beneficial to be able to use the the validation_split configuration during the KerasMember construction, just like the way Keras provides for its own models.

A concrete sample:

member1 = KerasMember(name="Model1", keras_model=model1, validation_split=0.2)

Many thanks for sharing this useful module with us. Thanks in advance for your consideration.