update pybind version

[lucasberent]

Description

This PR updates the minimum pybind11 version to 2.12, which was released a couple weeks ago and brings several big improvements, including compatibility with Numpy 2.0 which will be released soon, see cda-tum/mqt-qcec#383

Checklist:

• The pull request only contains commits that are related to it.
• I have added appropriate tests and documentation.
• I have made sure that all CI jobs on GitHub pass.
• The pull request introduces no new warnings and follows the project's style guidelines.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 84.7%. Comparing base (64d71a8) to head (71a6056).

Additional details and impacted files

@@          Coverage Diff          @@
##            main    #215   +/-   ##
=====================================
  Coverage   84.6%   84.7%           
=====================================
  Files         25      25           
  Lines       2023    2023           
  Branches     191     191           
=====================================
+ Hits        1713    1714    +1     
+ Misses       310     309    -1     

Flag	Coverage Δ
cpp	79.5% <ø> (ø)
python	88.8% <ø> (+<0.1%)	⬆️

see 1 file with indirect coverage changes