Drop support for Python 3.9 and 3.10

[MatthieuDartiailh]

Now irrelevant conditional version checks are also removed.

[codecov-commenter]

Codecov Report

❌ Patch coverage is 98.91304% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 95.16%. Comparing base (13032bb) to head (fa14851).

Files with missing lines	Patch %	Lines
src/bytecode/concrete.py	98.21%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #183      +/-   ##
==========================================
- Coverage   95.37%   95.16%   -0.22%     
==========================================
  Files           7        7              
  Lines        2142     2025     -117     
  Branches      483      452      -31     
==========================================
- Hits         2043     1927     -116     
+ Misses         56       54       -2     
- Partials       43       44       +1     

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