updating options does not override scales.yAxes[0].ticks.callback

Hello,

I have embedded ember-cli-chart in my hbs file as

```hbs

In my component file I have created an **options** property as
```javascript
options: computed('metric', function() {
let opts = defaultOptions;
if (this.metric === 'height') {
opts.scales.yAxes = [{
ticks: {
callback: function(value, index, values) {
// code to return labels
}
}
}]
} else {
opts.scales.yAxes = [{
ticks: {
callback: function(item, index, items) {
// code to return labels
}
}
}]
return opts;
}
});
```

So when first time chart loads it renders correct labels and if I change the metric then the same callback is getting used and renders same labels but with updated data values.
Can anyone help on this?