TPOT incompatible with current Numpy requirements

## Context of the issue

I did a pip install for tpot, however, when it tries to instantiate the class OneHotEncoder, the class has one input parameter of dtype, and it uses np.float. `np.float` was a deprecated alias for the builtin `float`.

## Process to reproduce the issue

1. pip install tpot
2. from tpot import TPOTRegressor
3. AttributeError: module 'numpy' has no attribute 'float'.