Update codecov/codecov-action action to v6 (#285)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

.github/workflows/ci.yml

@@ -148,7 +148,7 @@ jobs:
         run: make -j2 test
 
       - name: Publish Unit Test Coverage
-        uses: codecov/codecov-action@75cd11691c0faa626561e295848008c8a7dddffe # v5
+        uses: codecov/codecov-action@57e3a136b779b570ffcdbf80b3bdc90e7fab3de2 # v6
         with:
           flags: unittests
           file: _output/tests/linux_amd64/coverage.txt