title: Dictionary "Key" and "Value" properties names aren't being camel-case serialized
body: <p>When serializing a <code>List&lt;KeyValuePair&lt;string, string&gt;&gt;</code>, this is the JSON I am obtaining:</p>
  
  <pre><code>[
      {
          "Key": "Mineplex",
          "Value": "ULTRA"
      }
  ]
  </code></pre>
  
  <p>However, I'd like it to be <code>key</code> instead of <code>Key</code>, and <code>value</code> instead of <code>Value</code>.</p>
  
  <p>I am already using <code>JsonNamingPolicy.CamelCase</code>.</p>
  
  <p>How can I do?</p>