Update codecov/codecov-action action to v6

Author: renovate[bot]

.github/workflows/cpp-coverage.yml

@@ -64,7 +64,7 @@ jobs:
 
       # yamllint disable rule:line-length
       - name: Upload coverage reports to Codecov with GitHub Action
-        uses: codecov/codecov-action@75cd11691c0faa626561e295848008c8a7dddffe # v5
+        uses: codecov/codecov-action@57e3a136b779b570ffcdbf80b3bdc90e7fab3de2 # v6
         with:
           directory: ./coverage
           files: coverage/lcov.info