Update codecov/codecov-action action to v6

Author: renovate[bot]

.github/workflows/test.yml

@@ -50,7 +50,7 @@ jobs:
 
     - name: Upload coverage reports
       if: matrix.os == 'ubuntu-latest' && matrix.python-version == '3.12'
-      uses: codecov/codecov-action@v4
+      uses: codecov/codecov-action@v6
       with:
         file: ./coverage.xml
         flags: unittests