Add README.pt_br.md with Brazilian Portuguese translation

[ViniViniAntunes]

Describe the change
Added a new file README.pt_br.md, which provides a Portuguese translation of the original README.md (English version).
Also updated the reference link in the original README.md to include and point to the new translated version.

Additional context
This update aims to make the project more accessible to brazilians and Portuguese-speaking contributors and readers.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (503ec95) to head (3a2c74d).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff            @@
##              main      #143   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           36        36           
  Lines         1153      1153           
  Branches        62        62           
=========================================
  Hits          1153      1153           

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[huangsam]

Thanks @ViniViniAntunes for the translation! And I appreciate your adherence to the contributing guidelines