Consider adding a dependency on setuptools

[yakMM]

In whitelist.py, there is an import on pkg_resources from setuptools.

https://github.com/globality-corp/flake8-logging-format/blob/b7da42d1593ca19c5390be1e710439d0c45099ac/logging_format/whitelist.py#L5

This makes the code fail on environments without setuptools.

I suggest avoiding using the package altogether or making it a dependency (eventually optional)