Remove deprecated nitpick (#531)

* - ignore WPS437 Forbid protected attributes
and methods, for pytest files
- added mypy ignore thirdpary module

* - ignore WPS437 Forbid protected attributes
and methods, for pytest files
- added mypy ignore thirdpary module

* removed Nitpick after wemake python remove its support

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Co-authored-by: Killian Blais <codekoriko@users.noreply.github.com>

Author: codekoriko