update ci

Author: chengyupku

.github/workflows/ci.yml

@@ -115,11 +115,11 @@ jobs:
         source "${{ runner.tool_cache }}/${{ env.VENV_DIR }}/bin/activate"
         cd examples
         unset PYTHONPATH
-        python -m pytest -n 4 **/test*.py -v -r fE --durations=0 --cache-clear
+        python -m pytest -n 1 **/test*.py -v -r fE --durations=0 --cache-clear
 
     - name: Run tests
       run: |
         source "${{ runner.tool_cache }}/${{ env.VENV_DIR }}/bin/activate"
         cd testing/python
         unset PYTHONPATH
-        python -m pytest -n 4 -v -r fE --durations=0 --cache-clear --timeout=3600
+        python -m pytest -n 1 -v -r fE --durations=0 --cache-clear --timeout=3600