Use of `pkg_resources` is deprecated

https://github.com/fastai/nbdev/blob/96deb7a03bf2cf79a04e1878f67ce099e434e97f/setup.py#L5-L7

This is a friendly reminder, to tackle this in the future.

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https://setuptools.pypa.io/en/latest/pkg_resources.html

Use of pkg_resources is deprecated in favor of [importlib.resources](https://docs.python.org/3.11/library/importlib.resources.html#module-importlib.resources), [importlib.metadata](https://docs.python.org/3.11/library/importlib.metadata.html#module-importlib.metadata) and their backports ([importlib_resources](https://pypi.org/project/importlib_resources), [importlib_metadata](https://pypi.org/project/importlib_metadata)). Some useful APIs are also provided by [packaging](https://pypi.org/project/packaging) (e.g. requirements and version parsing). Users should refrain from new usage of pkg_resources and should work to port to importlib-based solutions.

Start with the linked lines 5–7 in setup.py and identify the current pkg_resources usage. Check the linked setuptools and Python importlib guidance, then verify that setup.py no longer relies on the deprecated API and that the project’s packaging checks still pass.

Written by the indexing model from the issue text.