title: React Select Typescript event type
body: <p>I have this handleSelect:</p>
  <pre><code>const handlerSelectBank = (event: React.ChangeEvent&lt;{ value: unknown }&gt;) =&gt; {
    setState({
      ...state,
      buttonDisabled: false,
      selectedBank: event
    });
  };
  </code></pre>
  <p>But I got this error:</p>
  <p><code>Type 'ChangeEvent&lt;{ value: unknown; }&gt;' is not assignable to type 'null'.ts(2322)</code></p>
  <p>This is the initial value of state:</p>
  <pre><code>const defaultState = {
    buttonDisabled: true,
    selectedBank: null
  };
  </code></pre>
  <p>What type should I use on <code>event</code>?</p>