[Proposal] Add pre-commit

[SauravMaheshkar]

Hey maintainers 👋🏽 ☕ , I noticed that most of (if not all) the steps of the Python Coding Style can be automated via pre-commit such as flake8 and pytest or even the ones in the GH actions such as mypy. Having pre-commit would make that process much easier and enforce that the developers follow coding conventions. Maybe this could even help with #67 if we add black as a hook

Additional context
Although this would add pre-commit as a dependency for the project.

[raphaelreinauer]

Thanks for the suggestion, @SauravMaheshkar ! Great idea. I have added pre-commit as a dependency in the project and a pre-commit config file. I have also added black as a hook. Let me know if there's anything else you think we should add.

[SauravMaheshkar]

#102 looks good 👍🏽