fixup! github-actions: add codecov upload

Co-authored-by: Alexandre Abadie <[email protected]>

Author: miri64

.github/workflows/tox.yml

@@ -34,3 +34,5 @@ jobs:
       uses: codecov/[email protected]
       with:
         flags: ${{ matrix.python-version }}
+        file: ./coverage.xml
+        fail_ci_if_error: true