Declare prettier as dependency of pre-commit hook

[brucellino]

Summary

This adds prettier as a dependency of the prettier pre-commit hook.

Turns out that the prettier configuration wants to be exported as a module, so the additional-dependencies in the pre-commit config don't get picked up.

I've declared explicit versions of Prettier for the pre-commit hook and added a devDependencies key in the package.json which was missing.

Related issue :

• https://github.com/prettier/prettier/issues/15388

Closed #640

[brucellino]

woops. Looks like I didn't discard the intermediate commits. Hope you squash this?

[brucellino]

@sebastian-luna-valero ready for review.