Fix code coverage upload name

Author: JohnGarbutt

.github/workflows/tox.yaml

@@ -41,5 +41,5 @@ jobs:
     - name: Archive code coverage results
       uses: actions/upload-artifact@v4
       with:
-        name: code-coverage-report
+        name: "code-coverage-report-${{ matrix.python-version }}"
         path: cover/