fix(validation): unnecessary constraint forcing root query type

[jjangga0214]

Currently, there is a constraint that forces people to provide root query type.

However, IMHO, it's unnecessary.

Mutation-and-subscription-only GraphQL is also possible.

Therefore, I patched it, to allow queryless schema.

More fundamentally speaking, why should you restrict people's intentions?

You cannot predict every use case, as the world is a quite complex place for a limited personal experience and a single philosophy to foresee.

Give people freedom.

JUST LET PEOPLE BUILD WHAT THEY WANT.

Thanks.

[Cito]

I hate to be a naysayer, but GraphQL.js has been created as a reference implementation for GraphQL, so it needs to follow the specification which says that the type system must contain a query type. Also, I think it is already possible to skip the schema validation by passing assumeValid=true.

[IvanGoncharov]

@Cito Thanks for the support 👍

@jjangga0214 I totally understand the frustration of being forced to add dummy field to Query type just to satisfy GraphQL specification.
That said as @Cito correctly pointed out we need to follow the spec so a way forward would be to first solve it in the spec.
Moreover, the proposal for this change is discussed here:
graphql/graphql-spec#631