Fix error when unmarshalling non optional bool on diff endpoint
Created by: eseliger
Graphql-Go logs the following error:
Could not unmarshal true (bool) into *bool: incompatible type
That is because the argument is non-optional in the schema, but a bool pointer in Go code. This has been introduced in 586b0ee3a0e4a6e5af2384f92efb4a299fd92da2.