Reformat with ruff

[jschlyter]

• Replace black & isort with ruff

Includes #166 (should be merged first)

[codecov]

Codecov Report

Attention: Patch coverage is 95.23810% with 4 lines in your changes missing coverage. Please review.

Project coverage is 76.24%. Comparing base (ef150b6) to head (69fed0a).
Report is 70 commits behind head on main.

Files with missing lines	Patch %	Lines
src/cryptojwt/tools/keygen.py	0.00%	2 Missing ⚠️
src/cryptojwt/key_issuer.py	75.00%	1 Missing ⚠️
src/cryptojwt/tools/jwtpeek.py	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #169      +/-   ##
==========================================
+ Coverage   76.21%   76.24%   +0.03%     
==========================================
  Files          44       44              
  Lines        4746     4484     -262     
  Branches     1000      984      -16     
==========================================
- Hits         3617     3419     -198     
+ Misses        824      777      -47     
+ Partials      305      288      -17     

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