Fix OS match for coverage upload

Author: duckontheweb

.github/workflows/continuous-integration.yml

@@ -37,7 +37,7 @@ jobs:
       - name: Upload All coverage to Codecov
         uses: codecov/codecov-action@v1
         # Only upload this once...
-        if: ${{ matrix.os == 'Linux' && matrix.python-version == '3.8'}}
+        if: ${{ matrix.os == 'ubuntu-latest' && matrix.python-version == '3.8'}}
         with:
           token: ${{ secrets.CODECOV_TOKEN }}
           file: ./coverage.xml