CI: Update codecov-action

Author: rhaschke

.github/workflows/ci.yaml

@@ -155,7 +155,7 @@ jobs:
           workdir: ${{ env.BASEDIR }}/target_ws
           ignore: '"*/target_ws/build/*" "*/target_ws/install/*" "*/test/*"'
       - name: Upload codecov report
-        uses: codecov/codecov-action@v5
+        uses: codecov/codecov-action@v6
         if: always() && matrix.env.CCOV && steps.ici.outputs.target_test_results == '0'
         with:
           files: ${{ env.BASEDIR }}/target_ws/coverage.info