Added a github action to run the pre-commit hook and display a diff on failure

[hello-robot-shehab]

• Also changed all the formatters to check and display a diff, instead of apply the fixes.
• Added a Contributing section to the README to explain how to install the pre-commit hook.

[hello-robot-shehab]

Pre-commit hook will pass when #91 is merged into this PR. Thanks!

Edit: we're removing formatters and linting checks that affect styling.

[hello-robot-shehab]

Merging this PR will always cause the github action to fail, unless we add feature/pre-commit...linting/isort-pass, is this okay with you? We could also just nuke the pre-commit hook entirely if you don't think it's worthwhile, thanks!

[hello-binit]

I think we can remove isort and keep the rest. My understanding of isort was that it would remove unnecessary imports only. From looking at its docs, it looks like the formatter is tightly integrated, and unnecessary imports are just one of many things it checks for.

[hello-robot-shehab]

I think we can remove isort and keep the rest. My understanding of isort was that it would remove unnecessary imports only. From looking at its docs, it looks like the formatter is tightly integrated, and unnecessary imports are just one of many things it checks for.

Done, thanks!

[hello-binit]

Looks like mypy isn't running. Any ideas why?

mypy.................................................(no files to check)Skipped