在Vagrant 2.0.4和2.1.1上，尝试安装此插件时会出现以下错误。 操作系统：Ubuntu 16.04
其他插件似乎正确安装。
Installing the 'vagrant-hostupdater' plugin. This can take a few minutes...
Bundler, the underlying system Vagrant uses to install plugins,
reported an error. The error is shown below. These errors are usually
caused by misconfigured plugin installations or transient network
issues. The error from Bundler is:
Unable to resolve dependency: user requested 'vagrant-hostupdater (> 0)'
我试过重新安装流浪汉。没运气。建议？