title: Ruby: nokogiri requires Ruby version < 3.1.dev, >= 2.5
body: <p>I'm trying to install the <a href="https://github.com/vagrant-libvirt/vagrant-libvirt" rel="nofollow noreferrer">Vagrant plugin</a> <code>vagrant-libvirt</code> on Debian 10. However, Debian 10 does only have Ruby <code>2.5</code> and I get the following error message each time I trigger <code>vagrant plugin install vagrant-libvirt</code>:</p>
  <pre><code>nokogiri requires Ruby version &lt; 3.1.dev, &gt;= 2.5.
  </code></pre>
  <p>I've installed all developer dependencies (<code>apt-get build-dep vagrant ruby-libvir</code>, <code>apt-get install libxslt-dev libxml2-dev libvirt-dev zlib1g-dev ruby-dev</code>) as required by the manual, but still get this error. Can anyone help me please?</p>