feat: modernize release process

[nijel]

Proposed changes

• use uv to build and publish packages
• use trusted publishing instead for stored token (currently not setup, waiting for @omab with this)
• build and lint packages on every commit, not only on release time

Types of changes

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• Release (new release request)
• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Code style update (PEP8, lint, formatting, renaming, etc)
• Refactoring (no functional changes, no api changes)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Build related changes (build process, tests runner, etc)
• Other (please describe):

Checklist

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• Lint and unit tests pass locally with my changes
• I have added tests that prove my fix is effective or that my feature works
• I have added documentation to https://github.com/python-social-auth/social-docs

Other information

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 77.91%. Comparing base (326d4b3) to head (26e1ad9).
Report is 8 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #954      +/-   ##
==========================================
+ Coverage   77.88%   77.91%   +0.02%     
==========================================
  Files         347      347              
  Lines       10669    10678       +9     
  Branches      504      504              
==========================================
+ Hits         8310     8320      +10     
- Misses       2200     2201       +1     
+ Partials      159      157       -2     

Flag	Coverage Δ
unittests	77.91% <ø> (+0.02%)	⬆️

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