Upload scalar return empty object as resolver argument

**Schema**

```
scalar Upload

type Mutation {
  uploadImage(image: Upload): Image
}
```

**Resolver**

This is the resolver to import `Upload` scalar

```js
const { GraphQLUpload } = require('graphql-upload');

module.exports = {
  Upload: GraphQLUpload
}
```

Resolver to handle image upload

```js
const uploadImage = input => {
  const data = { ...input }
  console.log(data)

  // upload to image server
}

module.exports = {
  uploadImage
}
```

The `Data` variable return `{ image: {} }` 

