Allow specifying the ContentType of the uploaded file

[N-Olbert]

Product

Strawberry Shake

Is your feature request related to a problem?

Within Hot Chocolate, the IFile interface, which is the server-side counterpart of the Upload scalar, has a property called ContentType. This property is populated with the Content-Type header of the HttpRequest itself, e.g., application/pdf.

Currently, this value cannot be specified via Strawberry Shake.

The solution you'd like

Allow specifying the content type of the uploaded file / the corresponding multipart http request from Strawberry Shake.
Therefore, StrawberryShake.Upload should be extended with a new member: string? ContentType.