chore(deps): update codecov/codecov-action action to v6

Author: renovate[bot]

.github/workflows/ci.yml

@@ -167,7 +167,7 @@ jobs:
         grcov . --output-type lcov --output-path "${COVERAGE_REPORT_FILE}" --binary-path "${COVERAGE_REPORT_DIR}" --branch
         echo "report=${COVERAGE_REPORT_FILE}" >> $GITHUB_OUTPUT
     - name: Upload coverage results (to Codecov.io)
-      uses: codecov/codecov-action@v5
+      uses: codecov/codecov-action@v6
       with:
         token: ${{ secrets.CODECOV_TOKEN }}
         files: ${{ steps.coverage.outputs.report }}