Add ROC AUC metric

[vincentmasse]

Pull Request Template

Checklist

• Confirmed that run-checks all script has been executed.
• Made sure the book is up to date with changes in this PR.

Related Issues/PRs

#544

Changes

Add ROC AUC metric for binary classification

Testing

Unit tests for the new metric.

[codecov]

Codecov Report

Attention: Patch coverage is 97.41935% with 4 lines in your changes missing coverage. Please review.

Project coverage is 82.94%. Comparing base (69de0ef) to head (823adb7).
Report is 8 commits behind head on main.

Files with missing lines	Patch %	Lines
crates/burn-train/src/metric/auroc.rs	97.41%	4 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2466      +/-   ##
==========================================
+ Coverage   82.79%   82.94%   +0.14%     
==========================================
  Files         809      811       +2     
  Lines      104191   105059     +868     
==========================================
+ Hits        86270    87136     +866     
- Misses      17921    17923       +2     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[laggui]

Thanks for the addition!

I have some minor comments, otherwise great start 🙂