[`flake8-use-pathlib`] Extend check for invalid path suffix to include the case `"."` (`PTH210`) (#14902)
## Summary
`PTH210` renamed to `invalid-pathlib-with-suffix` and extended to check for `.with_suffix(".")`. This caused the fix availability to be downgraded to "Sometimes", since there is no fix offered in this case.
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Co-authored-by: Micha Reiser <micha@reiser.io>
Co-authored-by: Dylan <53534755+dylwil3@users.noreply.github.com>