Add RISC-V architecture in GitHub CI

[s-trinh]

Add RISC-V architecture. There should be more development in the future with this architecture, especially from China due to potentially licensing conflict with Arm, e.g.

• https://github.com/opencv/opencv/wiki/OpenCV-RISC-V

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Suggestion to use ubuntu-latest.

Currently ubuntu-latest == ubuntu-22.04:

• Available images

• Standard GitHub-hosted runners for public repositories

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 45.25%. Comparing base (c1624ea) to head (6b4562e).
Report is 9 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1465      +/-   ##
==========================================
- Coverage   45.26%   45.25%   -0.01%     
==========================================
  Files        1121     1121              
  Lines      112131   112131              
  Branches    19077    19077              
==========================================
- Hits        50751    50750       -1     
- Misses      61380    61381       +1     

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[fspindle]

@s-trinh Thanks