docs(): add reference to GitHub action

[njelich]

Documenting GitHub Action, not sure how to reference it inside the ROFL Build section, since it doesnt even talk about installing the CLI, so I just mentioned it in the prerequisits. @matevz

Resolves oasisprotocol/docs#1638

[netlify]

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 48.54%. Comparing base (c54a9ef) to head (0cdef5e).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2425      +/-   ##
==========================================
- Coverage   48.55%   48.54%   -0.01%     
==========================================
  Files         224      224              
  Lines       16079    16079              
==========================================
- Hits         7807     7806       -1     
- Misses       8212     8213       +1     
  Partials       60       60              

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[matevz]

Prerequisites also do not seem an appropriate place, because it focuses on a developer setting up development environment on their machine.

Perhaps add it to https://docs.oasis.io/build/rofl/workflow/build under a new "Reproducible builds" section at the end and mention that developers can use the Oasis CLI github action as part of their CI/CD of the app.