Update codecov action to avoid warning

Author: gordonwatts

.github/workflows/ci.yml

@@ -55,7 +55,7 @@ jobs:
           python -m pytest -r sx
       - name: Report coverage with Codecov
         if: github.event_name == 'push' && matrix.python-version == 3.9 && matrix.os == 'ubuntu-latest'
-        uses: codecov/codecov-action@v1
+        uses: codecov/codecov-action@v3
         with:
           token: ${{ secrets.CODECOV_TOKEN }}
           file: ./coverage.xml