Enable `exhaustive-match` checks for `mypy`

[llucax]

What's needed?

It is good to have exhaustiveness checks when using the match statement, to make sure if the type is extended, no cases are left accidentally unhandled.

Proposed solution

Change the cookiecutter template to include:

[tool.mypy]
enable_error_code = ["exhaustive-match"]

Use cases

No response

Alternatives and workarounds

No response

Additional context

The new check will be probably released in mypy 1.17

• Add flag to raise error if match statement does not match exaustively python/mypy#19144