Switch from tag push to release publish for deploy pipeline

[nothingrandom]

Fixes mozilla/addons#15128

Switch from a flow where we push a tag to trigger a production deploy, to one where we create and publish a release.

And there's also a docs PR; mozilla/addons#16358

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 98.13%. Comparing base (fa7f695) to head (8950cf7).
⚠️ Report is 2 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master   #14352   +/-   ##
=======================================
  Coverage   98.13%   98.13%           
=======================================
  Files         269      269           
  Lines       10750    10750           
  Branches     3314     3314           
=======================================
  Hits        10550    10550           
  Misses        187      187           
  Partials       13       13           

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