Deprecate __version__ attribute

[Secrus]

Pull Request Check List

• Added tests for changed code.
• Updated documentation for changed code.

[codspeed-hq]

CodSpeed Performance Report

Merging #897 will not alter performance

_{Comparing Secrus:deprecate-version (a151d1a) with master (e57ca8e)}

Summary

✅ 1 untouched benchmarks

[ashb]

I kind of like having __version__ attrs in there, as importlib.metadata is surprisingly slow, but I guess not much should really be looking at version anyway

[Secrus]

I kind of like having __version__ attrs in there, as importlib.metadata is surprisingly slow, but I guess not much should really be looking at version anyway

Looking at version shouldn't be something one does too often, and I prefer we have a single (or rather reduce from 3 to 2) source of version.