To contribute to wordcloud, you'll need to follow the instructions in Creating a pull request from a fork.
In addition to the general procedure for creating a pull request, please follow the following steps:
Python 3.7.x should be fine for development.
python --version
> Python 3.7.6
pip install -U -r requirements.txt -r requirements-dev.txt
flake8
pip install -e .
pytest
flake8
pytest