Prepare for 1.20.0 release

[godlygeek]

See changelog for more details.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 92.39%. Comparing base (d6787da) to head (97044d7).

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #991      +/-   ##
==========================================
- Coverage   92.43%   92.39%   -0.04%     
==========================================
  Files         101      101              
  Lines       13199    13199              
  Branches      477      477              
==========================================
- Hits        12200    12195       -5     
- Misses        999     1004       +5     

Flag	Coverage Δ
cpp	92.39% <100.00%> (-0.04%)	⬇️
python_and_cython	92.39% <100.00%> (-0.04%)	⬇️

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[sarahmonod]

LGTM