Bump codecov/codecov-action from 5 to 6 (#587)

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

Author: dependabot[bot]

.github/workflows/test-coverage.yaml

@@ -47,7 +47,7 @@ jobs:
           covr::to_cobertura(cov)
         shell: Rscript {0}
 
-      - uses: codecov/codecov-action@v5
+      - uses: codecov/codecov-action@v6
         with:
           # Fail if error if not on PR, or if on PR and token is given
           fail_ci_if_error: ${{ github.event_name != 'pull_request' || secrets.CODECOV_TOKEN }}