add codecov token

Author: bchengxu

.github/workflows/codecov.yml

@@ -40,3 +40,5 @@ jobs:
     - name: Upload coverage reports to Codecov with GitHub Action
 #      if: ${{ runner.os == 'Linux' && matrix.python-version == 3.8 }}
       uses: codecov/codecov-action@v3
+      env:
+        CODECOV_TOKEN: ${{ secrets.CODECOV_TOKEN }}