Fix wf issue

Author: Peng Ren

.github/workflows/ci.yml

@@ -81,9 +81,10 @@ jobs:
         python -m pytest tests/ --cov=pymongosql --cov-report=term-missing --cov-report=xml
 
     - name: Upload coverage reports
-      if: github.event_name == 'push' && ${{ secrets.CODECOV_TOKEN }}
-      uses: codecov/codecov-action@v3
+      uses: codecov/codecov-action@v4
       with:
+        env_vars: OS,PYTHON
         token: ${{ secrets.CODECOV_TOKEN }}
-        file: ./coverage.xml
+        files: ./coverage.xml
+        flags: unittests
         fail_ci_if_error: false