Type annotations and mypy
🚀 Feature

Introduce mypy in pre-commit pipeline
Motivation
Static type checking is an interesting and powerful technique to assure high code quality and standard. I believe it should be unvaluable to start introducing type annotation and add mypy among pre-commit hooks

Pitch
I want to check the correctness of types annotation with a static type checking. When I commit, the checker should verify and eventually notify the contributer to check his code

Alternatives

Additional context

I ran mypy onto tests and it heighights some deprecated calls (such as checkpoint_callback, now in callbacks list). These checks could be useful to static check tests and find avoid obsolescent tests