Set Data Source on a Layer via API
Hello,

I am wondering if it is possible with the Sketch API to set a layer to use a specific data supplier data source programatically? i.e. Replicate what Sketch is doing when a user selects a `Data Feed` for the layer - but I want to be able to do that from my plugin, in order to perform several steps at once.

In my plugin, I register a data supplier:
`index.js`
```
  DataSupplier.registerDataSupplier(
    'public.text',
    'Auto (Layer Name)',
    'SupplyAutomatically'
  );
```

And I want to know if I can set a layer to use that data supplier via the API.

Thanks,

Paul