message: Update containerSelector codesandbox
diff: @@ -219,11 +219,11 @@ const embla = EmblaCarousel(emblaNode, options)
  </div>
  <br>
  <div>
  - <a href="https://codesandbox.io/s/embla-carousel-containerselector-my-classname-ntlzb">
  + <a href="https://codesandbox.io/s/embla-carousel-containerselector-ntlzb">
  <img src="https://rawgit.com/davidcetinkaya/embla-carousel/master/docs/assets/codesandbox-logo.svg" height="23" align="top" alt="Embla Carousel CodeSandbox" />
  </a>
  &nbsp;
  - <a href="https://codesandbox.io/s/embla-carousel-containerselector-my-classname-ntlzb">
  + <a href="https://codesandbox.io/s/embla-carousel-containerselector-ntlzb">
  <code>CodeSandbox</code>
  </a>
  </div>
  @@ -234,13 +234,13 @@ const embla = EmblaCarousel(emblaNode, options)
  ```javascript
  const emblaNode = document.querySelector('.embla')
  -const options = { containerSelector: '.my-classname' }
  +const options = { containerSelector: '.my-container-selector' }
  const embla = EmblaCarousel(emblaNode, options)
  ```
  ```html
  <div class="embla">
  - <div class="my-classname">
  + <div class="my-container-selector">
  ...slides
  </div>
  </div>
  