add mypy to pre-commit - #639

[jGaboardi]

This PR resolves #639

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 98.1%. Comparing base (4037c70) to head (559e35d).
Report is 88 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##            main    #640     +/-   ##
=======================================
+ Coverage   97.4%   98.1%   +0.8%     
=======================================
  Files         26      38     +12     
  Lines       4328    6203   +1875     
=======================================
+ Hits        4214    6088   +1874     
- Misses       114     115      +1     

[martinfleis]

I am not sure I am fan of this... Linting is easy to fix, typing may be harder. And if you have pre-commit hook installed locally, this won't allow you to commit and push to ask in the PR what the typing should be.