Fix badge URL

[AdrienVannson]

Summary

The badge always shows the build as failing, even if it is actually successful.

This issue has been reported on https://github.com/actions/starter-workflows/issues/1525 , and the fix suggested on https://github.com/actions/starter-workflows/issues/1525#issuecomment-1763431305 works.

Checklist

• [ ] If code changes were made then they have been tested.
  • [ ] I have updated the documentation to reflect the changes.
• [ ] This PR fixes an issue.
• [ ] This PR adds something new (e.g. new method or parameters).
  • [ ] This change has an associated test.
• [ ] This PR is a breaking change (e.g. methods or parameters removed/renamed)
• [X] This PR is not a code change (e.g. documentation, README, ...)