我使用Packer vsphere-iso构建器通过配置shell程序在 vSphere 上构建 Ubuntu-18.04 VM ，当我运行以下两个命令之一时：
sudo apt-get install software-properties-common --yes
sudo apt-get install ca-certificates curl gnupg lsb-release --yes
我收到以下错误：
==> vsphere-iso.ubuntu-18_04-base-template: debconf: unable to initialize frontend: Dialog
==> vsphere-iso.ubuntu-18_04-base-template: debconf: (Dialog frontend will not work on a dumb terminal, an emacs shell buffer, or without a controlling terminal.)
==> vsphere-iso.ubuntu-18_04-base-template: debconf: falling back to frontend: Readline
==> vsphere-iso.ubuntu-18_04-base-template: debconf: unable to initialize frontend: Readline
==> vsphere-iso.ubuntu-18_04-base-template: debconf: (Can't locate Term/ReadLine.pm in @INC …