title: How can I create nested option groups in React Select (V2)?
body: <p>In React-Select V2, we're able to create option groups by passing an <code>options</code> param like so:</p>
  
  <pre><code>options = [
      { label: 'Group', options: [
          { label: 'Option 1', value: '1' },
          { label: 'Option 2', value: '2' }
      ]}
  ]
  </code></pre>
  
  <p>I need to be able to go another layer deep, something like:</p>
  
  <pre><code>options = [
      { label: 'Group', options: [
          { label: 'Option 1', value: '1' },
          { label: 'Option 2', options: [
              { label: 'Option 2-a', value: '2a' },
              { label: 'Option 2-b', value: '2b' },
          ]}
      ]}
  ]
  </code></pre>
  
  <p>Which would display the options "Option 2-a" and "Option 2-b" in a group under "Option 2". The approach above doesn't work out of the box, so I want to know if there's a way to create nested groups in React-Select V2.</p>