Issue uploading a file with non-English filename
```
var my_graphQL_func = {
  type: responseType,
  args: {
	file_upload: { type : GraphQLUpload, required: true }
  },
  resolve: async (_, args) => {
	  ...
    console.log( args.file_upload )
	...
  }
```

I am using GraphQLUpload. Everything works ok, but whenever I upload a file that contains non-English characters in the file's name, the app seems to . For example, I got a file named "平仮名.pdf". When I uploaded it in, this is what I got from console.log above:

```
Promise {
  { filename: 's�\r.pdf',
    mimetype: 'application/pdf',
    encoding: '7bit',
    createReadStream: [Function: createReadStream] } }
```

So "平仮名.pdf" became "s�\r.pdf" . This occurs with other languages as well. How do I fix this issue? 