Replace deprecated imp module with importlib

[hugovk]

Expected behaviour

Works with Python 3.12.

Actual behaviour

This project uses the imp module which has been deprecated since Python 3.4 and removed in 3.12:

• Raised PendingDeprecationWarning since 3.4 (2014)
• Raised DeprecationWarning since 3.5 (2015)
• Updated DeprecationWarning to say removal in 3.12 since 3.10 (2021)
• Removal planned for 3.12 (2023)

Python 3.12 is set for release on 2023-10-02 and this library is one of the top 5,000 most-downloaded from PyPI.

Please could you upgrade to use importlib? The imp docs have suggestions on what to use to replace each function and constant.

What are the steps to reproduce this issue?

Input clear steps to reproduce the issue for a maintainer.

1. git grep "\bimp\b"

https://github.com/python-social-auth/social-core/blob/706c9e363387298ab6623c250e6e05b759bfba24/social_core/backends/shopify.py#L27-L28

[nijel]

Actually, I don't see a reason for not using import directly.