title: Vue-Cli: 'title' option for htmlWebpackPlugin does not work
body: <p>I'm using vue-cli (3.4.1) and I'm trying to simply change the title of the document.</p>
  <p>I added the following to the vue.config.js</p>
  <pre class="lang-js prettyprint-override"><code>    chainWebpack: (config) =&gt; {
          config
            .plugin('html')
            .tap((args) =&gt; {
              args[0].title = 'Custom Title';
              return args;
            });
        },
  </code></pre>
  <p>and inspected the webpack config with <code>vue inspect --plugin html</code> resulting in the following output</p>
  <pre class="lang-js prettyprint-override"><code>    /* config.plugin('html') */
      new HtmlWebpackPlugin(
        {
          templateParameters: function () { /* omitted long function */ },
          template: '&lt;path&gt;\node_modules\\@vue\\cli-service\\lib\\config\\index-default.html',
          title: 'Custom Title'
        }
      )
  </code></pre>
  <p>The title of the Webapp still says &quot;Vue App&quot;.</p>
  <p>Any ideas why?</p>
  <p>PS: I do not want to set <code>document.title = 'Custom Title'</code> somewhere in my app. I want the title between the <code>&lt;title&gt;</code>-tags in the <code>&lt;head&gt;</code> element of the document to be altered at build time.</p>