Using multiple arguments causes "Variable XXX got invalid value { resolve: [function], reject: [function], promise: {} }"
I'm using `graphql-upload` with NestJS, everything works fine if I have just one graphql argument in the file upload mutation. In my case I also need to send a `type` argument as a String to know in the server-side how I should handle this upload.

When I add this new argument in the mutation and send it in to the request I start having this error `Variable \"$type\" got invalid value { resolve: [function], reject: [function], promise: {} }`. I wasn't able to dig into `graphql-upload` source code to find out what's happening under the hood.

<img width="1258" alt="Screen Shot 2022-05-23 at 9 41 25 PM" src="https://user-images.githubusercontent.com/2160382/169926022-bb29e135-1a8b-4124-bae4-1abec24f8f00.png">

If I remove `type` argument from the mutation and from Postman request I get the file uploaded without errors.

Repro: https://github.com/pedropapa/github-upload-issue-repro