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

Author: renovate[bot]

.github/workflows/ci.yml

@@ -36,7 +36,7 @@ jobs:
         run: go test -v -race -coverprofile=coverage.txt -covermode=atomic ./...
 
       - name: Upload coverage to Codecov
-        uses: codecov/codecov-action@v5
+        uses: codecov/codecov-action@57e3a136b779b570ffcdbf80b3bdc90e7fab3de2 # v6
         with:
           files: ./coverage.txt
           flags: unittests