ci(tests): update codecov action version to 6.0.0

Author: SlimDeluxe

.github/workflows/test-runner.yml

@@ -73,7 +73,7 @@ jobs:
       - name: Upload coverage reports to Codecov
         # Make sure the Codecov action is only executed once
         if: matrix.os == 'ubuntu-latest' && matrix.php == '7.4'
-        uses: codecov/codecov-action@v3
+        uses: codecov/codecov-action@v6.0.0
         with:
           files: ./coverage.xml
           verbose: true