Install setuptools manually for Python 3.12 compatibility

Author: foarsitter

.github/workflows/ci.yml

@@ -81,7 +81,7 @@ jobs:
       - name: Install dependencies
         run: |
           python -m pip install --upgrade pip
-          python -m pip install --upgrade tox tox-gh-actions
+          python -m pip install --upgrade tox tox-gh-actions setuptools
 
       - name: Tox tests
         run: |