Reflect changes and content of files involved in packaging as defined by PEP 517/518 specification

[search5]

Expected behaviour

With recent changes to the Python packaging specification to allow the use of different backends, installing packages using setup.py often results in warning messages.

Actual behaviour

Regardless of your Python version, you will need to update your packaging specification to follow the latest Python packaging specification, PEP 517/518.

What are the steps to reproduce this issue?

There is no separate error implementation procedure for packaging specification changes, as they are not considered errors and can be categorized as feature enhancements.

Any other comments?

I'm working on changing the SQLAlchemy 1 version code to SQLAlchemy 2 version code in several subprojects of the Python-social-auth project, and I'd like to reflect this in the corresponding commits.