Update release creation docs

[clelange]

Release creation is automated via GitHub actions but this is not yet reflected in the documentation.

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📚 Documentation preview 📚: https://hepdata-lib--269.org.readthedocs.build/en/269/

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 90.42%. Comparing base (24863e9) to head (f3a0b78).
Report is 4 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #269   +/-   ##
=======================================
  Coverage   90.42%   90.42%           
=======================================
  Files           5        5           
  Lines        1117     1117           
  Branches      254      254           
=======================================
  Hits         1010     1010           
  Misses         78       78           
  Partials       29       29           

Flag	Coverage Δ
unittests-3.10	90.42% <ø> (ø)
unittests-3.11	90.42% <ø> (ø)
unittests-3.6	90.14% <ø> (ø)
unittests-3.7	90.14% <ø> (ø)
unittests-3.8	90.24% <ø> (ø)
unittests-3.9	90.24% <ø> (ø)

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