[REF] Allow this repo to be a pre-commit hook

[fernandahf]

With these changes, this repo will be used as a hook in pre-commit.

[fernandahf]

For record:

The tests worked fine!

cc @moylop260

[fernandahf]

@markdrago

Could you take a look at this, please?

Those little changes allow using this repo as the hook of https://github.com/pre-commit/pre-commit

More info:

https://pre-commit.com/#new-hooks

[moylop260]

@markdrago

What do you think?