Project does not contain a handler function named: onRun
I recently updated the dependencies on my project to be:

```
"devDependencies": {
    "@skpm/builder": "^0.5.4",
    "@skpm/extract-loader": "^2.0.2",
    . . .
}
"dependencies": {
    "sketch-module-web-view": "^1.1.4"
}
```

But now I'm getting this error that I didn't have before. Would it be related to the updates?
```
Error in command Search in Polaris Script at path ...Contents/Sketch/plugin.js does not contain a handler function named: onRun.
```

My `plugin.js` only exports default a function but it seems to be looking for `onRun`.

```
export default function(context) {
  . . . 
}
```

cc @mathieudutour 