CI: enhance nightly backward compatibility testing workflow

[dlachaume]

Content

This PR includes...

Pre-submit checklist

• Branch
  • [ ] Tests are provided (if possible)
  • [ ] Crates versions are updated (if relevant)
  • [ ] CHANGELOG file is updated (if relevant)
  • [ ] Commit sequence broadly makes sense
  • [ ] Key commits have useful messages
• PR
  • [ ] No clippy warnings in the CI
  • [ ] Self-reviewed the diff
  • [ ] Useful pull request description
  • [ ] Reviewer requested
• Documentation
  • [ ] Update README file (if relevant)
  • [ ] Update documentation website (if relevant)
  • [ ] Add dev blog post (if relevant)

Issue(s)

Relates to #YYY or Closes #YYY

[github-actions[bot]]

Test Results

    4 files  ±0     51 suites  ±0   10m 29s ⏱️ -1s 1 400 tests ±0  1 400 ✅ ±0  0 💤 ±0  0 ❌ ±0  1 611 runs  ±0  1 611 ✅ ±0  0 💤 ±0  0 ❌ ±0 

Results for commit a87b48c4. ± Comparison against base commit bd9b7be4.

:recycle: This comment has been updated with latest results.