[WIP] Update governance after election + clarifications

[OriolAbril]

Thank your for opening a PR!

Depending on what your PR does, here are a few things you might want to address in the description:

• what are the (breaking) changes that this PR makes?
• important background, or details about the implementation
• are the changes—especially new features—covered by tests and docstrings?
• linting/style checks have been run
• consider adding/updating relevant example notebooks
• right before it's ready to merge, mention the PR in the RELEASE-NOTES.md

[codecov]

Codecov Report

Merging #5136 (9c40e89) into main (21e1998) will increase coverage by 1.21%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##             main    #5136      +/-   ##
==========================================
+ Coverage   77.74%   78.95%   +1.21%     
==========================================
  Files          88       88              
  Lines       14100    14256     +156     
==========================================
+ Hits        10962    11256     +294     
+ Misses       3138     3000     -138     

Impacted Files	Coverage Δ
pymc/step_methods/hmc/integration.py	78.84% <0.00%> (-3.85%)	⬇️
pymc/tests/backend_fixtures.py	77.55% <0.00%> (-1.43%)	⬇️
pymc/bart/pgbart.py	95.14% <0.00%> (-1.10%)	⬇️
pymc/parallel_sampling.py	86.33% <0.00%> (-1.00%)	⬇️
pymc/step_methods/hmc/nuts.py	95.00% <0.00%> (-0.63%)	⬇️
pymc/tests/sampler_fixtures.py	90.76% <0.00%> (-0.48%)	⬇️
pymc/model.py	83.30% <0.00%> (-0.45%)	⬇️
pymc/aesaraf.py	89.70% <0.00%> (-0.41%)	⬇️
pymc/step_methods/metropolis.py	82.83% <0.00%> (-0.08%)	⬇️
pymc/smc/smc.py	98.30% <0.00%> (-0.05%)	⬇️
... and 20 more