Readme code is broken

```js
// it needs require('multi-regl')() call here
const multiREGL = require('multi-regl')

const div1 = document.createElement('div')
div1.style.width = '500px'
div1.style.height = '500px'
document.body.appendChild(div1)

const regl1 = multiREGL(div1)

regl1.frame(() => {
  regl1.clear({
    color: [1, 0, 0, 1],
    depth: 1
  })
})
```