MNT: hotfix CI by setting an upper limit to setuptools version

tests/ci_install.sh

@@ -42,7 +42,7 @@ if [[ "${RUNNER_OS}" == "Windows" ]] && [[ ${dependencies} != "minimal" ]]; then
 else
  python -m pip install --upgrade pip
  python -m pip install --upgrade wheel
- python -m pip install --upgrade setuptools
+ python -m pip install --upgrade setuptools<58.0 # see https://github.com/pypa/setuptools/issues/2775
 fi
 
 # Step 2: install deps and yt