MAINT: Revamp the CI pypi/test-pypi release workflow.

[arokem]

Secrets already added to the repo, so this should work on merge.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 59.76%. Comparing base (c4a6282) to head (d3a88f3).
⚠️ Report is 6 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master      #92      +/-   ##
==========================================
+ Coverage   58.96%   59.76%   +0.79%     
==========================================
  Files          12       12              
  Lines        2364     2411      +47     
==========================================
+ Hits         1394     1441      +47     
  Misses        970      970              

Flag	Coverage Δ
unittests	59.76% <ø> (+0.79%)	⬆️

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[arokem]

I also added the "Package deployment" environment to the repo and added @francopestilli , @frheault , @neurolabusc , @skoudoro as people who can click the release button when releases are ready to go up to pypi.