title: Object is of type 'unknown'. on Gridsome
body: <p>Developing on gridsome
  this page reports typescript errors on $static</p>
  <pre><code>&lt;script src=&quot;https://cdnjs.cloudflare.com/ajax/libs/vue/2.5.17/vue.js&quot;&gt;&lt;/script&gt;
  &lt;template&gt;
    &lt;div class=&quot;layout&quot;&gt;
      &lt;header class=&quot;header&quot;&gt;
        &lt;strong&gt;
          &lt;g-link to=&quot;/&quot;&gt;{{ $static.metadata.siteName }}&lt;/g-link&gt;
        &lt;/strong&gt;
        &lt;nav class=&quot;nav&quot;&gt;
          &lt;g-link class=&quot;nav__link&quot; to=&quot;/&quot;&gt;Home&lt;/g-link&gt;
          &lt;g-link class=&quot;nav__link&quot; to=&quot;/about/&quot;&gt;About&lt;/g-link&gt;
        &lt;/nav&gt;
      &lt;/header&gt;
      &lt;p&gt;Description: {{ $static.metadata.siteDescription }}&lt;/p&gt;
      foo 
      &lt;slot/&gt;
    &lt;/div&gt;
  &lt;/template&gt;
  </code></pre>