File/Blob data sent as variable does not support inside the resolver
I tried sending the File constructor or even tried converting to File object to blob using it inside the mutation as a variable.

But in the I get the data from the resolver in this format:

```
{ resolve: [Function],
  reject: [Function],
  promise:
   Promise {
     { filename: 'tumblr_d33bd9ecbbd25a9417e96e0c2ae70f17_d068b0da_500.png',
       mimetype: 'image/png',
       encoding: '7bit',
       createReadStream: [Function: createReadStream] } },
  file:
   { filename: 'tumblr_d33bd9ecbbd25a9417e96e0c2ae70f17_d068b0da_500.png',
     mimetype: 'image/png',
     encoding: '7bit',
     createReadStream: [Function: createReadStream] } }
```

While trying to use this with `aws-sdk` package, it shows error

```
[InvalidParameterType: Expected params.documents to be a string, Buffer, Stream, Blob, or typed array object]
```

I am not sure if the `graphql-upload` data type is sending the correct data type.