fixup! github-actions: add codecov upload

Author: miri64

.github/workflows/tox.yml

@@ -31,9 +31,9 @@ jobs:
     - name: Test with tox
       run: tox
     - name: Upload to coverage
-      uses: codecov/[email protected]
-      with:
-        flags: ${{ matrix.python-version }}
+      env:
+        CODECOV_FLAGS: ${{ matrix.python-version }}
+      run: bash <(curl -s https://codecov.io/bash)
     - name: Publish package to PyPI
       uses: pypa/gh-action-pypi-publish@master
       if: >-