Environment bug fix. Reinstall CityLearn to bump version from 1.3.0 to 1.3.1

[kingsley_nweye]

A recent bug fix has been implemented in the CityLearn environment. Please, upgrade the CityLearn environment by executing:

pip install git+https://github.com/intelligent-environments-lab/CityLearn.git@v1.3.1

The fixed bugs are:

1. Spelling error in reward_function.py that cause electricity_consumption variable to be unspecified.

See https://github.com/intelligent-environments-lab/CityLearn/compare/v1.3.0…v1.3.1 for full change log.