Use importlib (Python 3.12 compatible)

[Kilo59]

Replace imp usage with importlib
imp has been removed in Python 3.12 so this should make this package compatible.

• Remove Python 2 compatibility code #142 (comment)

Tests all pass locally on Python 3.12.

• This implementation is much simpler than Use importlib instead of imp #168

[RobinTail]

Fixes #166

[jeremyk]

Any update on this? Would be really nice to get it merged.

[ayys]

@Kilo59 I am closing this as duplicate of #168, since the other PR is now merged.