Update codecov/codecov-action action to v3.1.6

Author: renovate[bot]

.github/workflows/unit-test.yml

@@ -28,4 +28,4 @@ jobs:
     - name: npm test
       run: npm test
     - name: Upload coverage to Codecov
-      uses: codecov/codecov-action@v3.1.4
+      uses: codecov/codecov-action@v3.1.6