sklearn FutureWarning for deprecated SCORERS attribute

[ZviBaratz]

Usage of of SCORERS in tpot.metrics causes sklearn to raise:

FutureWarning: sklearn.metrics.SCORERS is deprecated and will be removed in v1.3. Please use sklearn.metrics.get_scorer_names to get a list of available scorers and sklearn.metrics.get_metric to get scorer.

A possible fix for this would be to simply recreate the SCORERS attribute using the get_scorer_names() and get_scorer() methods. I'm happy to come up with a PR.