Add black (cd sdk/evaluation/azure-ai-evaluation && tox run -e black -c ../../../eng/tox/tox.ini --root .) as a pre-commit for azure-ai-evaluation sdk

Add black (cd sdk/evaluation/azure-ai-evaluation && tox run -e black -c ../../../eng/tox/tox.ini --root .) as a pre-commit for azure-ai-evaluation sdk #168