ray_py38 python env lacks tabulate

A. Adelmann wants to use ray.tune which requires tabulate support

In [1]: from ray import tune
...
/opt/psi/Programming/anaconda/2019.07/conda/envs/ray_py38.yml/lib/python3.8/site-packages/ray/tune/progress_reporter.py in <module>
     21     from tabulate import tabulate
     22 except ImportError:
---> 23     raise ImportError("ray.tune in ray > 0.7.5 requires 'tabulate'. "
     24                       "Please re-run 'pip install ray[tune]' or "
     25                       "'pip install ray[rllib]'.")

ImportError: ray.tune in ray > 0.7.5 requires 'tabulate'. Please re-run 'pip install ray[tune]' or 'pip install ray[rllib]'.