registry.py: migrate deprecated pkg_resources

[hseg]

As noted in https://setuptools.pypa.io/en/latest/pkg_resources.html, pkg_resources is deprecated. We were only using it for iter_entry_points anyway, which has been moved to importlib.metadata:entry_points

Changes proposed in this pull request:

• Replace pkg_resources:iter_entry_points by importlib.metadata:entry_points

@xlcnd

[KenjiTakahashi]

FYI: Since 3.12, pkg_resources is no longer part of stdlib and setuptools are not a part of the standard Python distribution either. Means that to be able to use isbnlib one needs to pip install setuptools first.

[pierreay]

Hello. Two years without any commit. Is isbnlib still maintained?

[rerowep]

Could you please merge this PR?

[hans-fritz-pommes]

Did you see the time of the last contribution of xlcnd and their profile?
I fear they fell in Putin - Ukraine war...

[hans-fritz-pommes]

I have created a fork and am now trying to maintain it.
https://github.com/hans-fritz-pommes/isbnlib
You can install it with pip install isbnlib2.
Maybe remove isbnlib before.
The module name is the same - your code will run the same way.