title: Dropdown onchange doesnt work : React+ Typescript+ semantic-ui-react
body: <p>I am trying to bring up a dropdown using semantic-ui-react with typescript. The problem here I am facing is , I am unable to attach change handlers to it. It is throwing the following error <em>" Type 'SyntheticEvent' is not assignable to type 'ChangeEvent' "</em>.</p>
  
  <pre><code>//Importing Dropdown
  import Dropdown from 'semantic-ui-react/dist/commonjs/modules/Dropdown';
  
  //options array
  const options = [
    { key: 1, text: 'Location 1', value: 1 },
    { key: 2, text: 'Location 2', value: 2 },
    { key: 3, text: 'Location 3', value: 3 },
  ]
  
  //state object
  this.state ={
    value : ''
  }
  
  //Dropwdown change event
  dropdownChange = (event: React.ChangeEvent&lt;HTMLSelectElement&gt; ,{value}) =&gt;{
     this.setState({ value });
  }
  
  //Rendering Drop down
  render()
  {
    return(
        &lt;Dropdown  
          options={opitons}
          name="value"  
          value={this.state.value}
          onChange={this.dropdownChange}
        /&gt;
    )
  }
  </code></pre>