title: How can I display currency with decimal and without it in vue-i18n
body: <p>With the following configuration I can output an amount with a currency</p>
  
  <pre><code>const numberFormats = {
      "en-GB": {
          currency: {
              style: 'currency', currency: 'GBP'
          }
      },
      "en-US": {
          currency: {
              style: 'currency', currency: 'USD'
          }
      }
  }
  </code></pre>
  
  <p>inside a component</p>
  
  <pre><code>&lt;p&gt;{{ $n(100.20, 'currency') }}&lt;/p&gt;
  </code></pre>
  
  <p>I can output:</p>
  
  <pre><code>&lt;p&gt;£100.20&lt;/p&gt;
  </code></pre>
  
  <p>the following format can be fine on some cases but if I need to output simple amounts like: £5, £10 ect.. I cannot. I tried to configure it with no success.</p>