Federation: Entity type is not shareable / Resolver generated for non-resolvable @key

When defining two subgraphs implementing the same @key directive on the same type:

type SomeEntity @key(fields: "id", resolvable: false) {
id: ID!
}

registering the generated schema in apollographql results in an error message:

UNKNOWN: Non-shareable field "Entity.findSomeEntityByID" is resolved from multiple subgraphs: it is resolved from subgraphs "schema1" and "schema2" and defined as non-shareable in all of them

There are two issues with this:
1. Since resolvable is false, no resolver should be generated
2. If a resolver is generated, it probably should be marked shareable (in https://github.com/99designs/gqlgen/blob/master/plugin/federation/federation.go#L166 )

- `go run github.com/99designs/gqlgen version`?
v0.17.4

- `go version`?
go version go1.19 darwin/arm64