CatBoostRegressor.subsample should be Float64

[liuyxpp]

According to CatBoost doc, it should be a floating number in the range (0, 1].

The proof is if you set an integer larger than 1 to subsample and train, you will get the error:

Python: CatBoostError: /src/catboost/catboost/private/libs/options/bootstrap_options.cpp:5: Subsample should be in (0,1]

[ericphanson]

Can you add a test that uses the functionality? To ensure we don’t regress

[ablaom]

@liuyxpp any chance of adding that test?