CollectionView does not relayout when setting an image on it

### Problem description

Setting an image on the `CollectionView` does not relayout the cell height when `cellHeight` is auto.

### Expected behavior

The cell should grow to accommodate the layout created with the applied image.

### Environment

- Tabris.js version: 3.0.0-beta2
- Device: iPhone 6
- OS: iOS 12

### Code snippet

```javascript
import {CollectionView, contentView, ImageView} from 'tabris';

contentView.append(
}
updateCell={(cell, index) => cell.image = 'resources/salad.jpg'}/>
);

```