Wrong documentation or miss understanding ?
Hi!
I was reading your documentation and there, you show that FileUpload interface is an interface with: 
- filename: string;
- mimetype: string;
- encoding: string;
- createReadStream: FileUploadCreateReadStream
However, on index.d.ts, you show that interface FileUpload consists of:
- filename: string;
- mimetype: string;
- encoding: string;
- createReadStream(): ReadStream

So, what happens ? When I try to do a stream like `const stream = file.createReadStream()`, I have an exception like "file.createReadStream is not a function".

package.json
graphql-upload@^13.0.0
@types/graphql-upload@^8.0.7