教程更新了？怎么 Homestead 检出的版本变成 7.8.0 了？然后 Vagrant up 提示 Vagrant 版本太低

$ cd ~/Homestead/ &&vagrant up
==> vagrant: A new version of Vagrant is available: 2.1.1!
==> vagrant: To upgrade visit: https://www.vagrantup.com/downloads.html

This Vagrant environment has specified that it requires the Vagrant
version to satisfy the following version requirements:

= 2.1.0

You are running Vagrant 2.0.2, which does not satisfy
these requirements. Please change your Vagrant version or update
the Vagrantfile to allow this Vagrant version. However, be warned
that if the Vagrantfile has specified another version, it probably has
good reason to do so, and changing that may cause the environment to
not function properly.