Bump codecov/codecov-action from 5.5.3 to 6.0.0 (#73)

Bumps [codecov/codecov-action](https://github.com/codecov/codecov-action) from 5.5.3 to 6.0.0.
- [Release notes](https://github.com/codecov/codecov-action/releases)
- [Changelog](https://github.com/codecov/codecov-action/blob/main/CHANGELOG.md)
- [Commits](codecov/codecov-action@1af5884...57e3a13)

---
updated-dependencies:
- dependency-name: codecov/codecov-action
  dependency-version: 6.0.0
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

.github/workflows/stage-2-test.yaml

@@ -39,7 +39,7 @@ jobs:
         run: uv run pytest
 
       - name: Upload coverage reports
-        uses: codecov/codecov-action@1af58845a975a7985b0beb0cbe6fbbb71a41dbad # v5.5.3
+        uses: codecov/codecov-action@57e3a136b779b570ffcdbf80b3bdc90e7fab3de2 # v6.0.0
         if: always()
         with:
           files: ./coverage.xml