build(deps): bump codecov/codecov-action in the actions group

Bumps the actions group with 1 update: [codecov/codecov-action](https://github.com/codecov/codecov-action).


Updates `codecov/codecov-action` from 5 to 6
- [Release notes](https://github.com/codecov/codecov-action/releases)
- [Changelog](https://github.com/codecov/codecov-action/blob/main/CHANGELOG.md)
- [Commits](codecov/codecov-action@v5...v6)

---
updated-dependencies:
- dependency-name: codecov/codecov-action
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
  dependency-group: actions
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

.github/workflows/coverage.yml

@@ -71,7 +71,7 @@ jobs:
           path: build
 
       - name: Upload coverage report
-        uses: codecov/codecov-action@v5
+        uses: codecov/codecov-action@v6
         with:
           token: ${{ secrets.CODECOV_TOKEN }}
           files: build/stdgpu_coverage.info