/opt/python3.7/bin/python3.7: No module named pip

GCP Cloud Functions使用python3.7部署時出現以下錯誤訊息

錯誤訊息：
部署失敗：

Build failed: `pip_install_from_wheels` had stderr output:

/opt/python3.7/bin/python3.7: No module named pip

error: `pip_install_from_wheels` returned code: 1; Error ID: ECB5F712

解決方式：
換成python3.8