Empty Input Type for many to many relationship join tables

After excecute npx prisma generate we have some Input Types that's are empty, so, when i tried to run the nest app i have the following Error:

```
[Nest] 4976 - 2020-10-16 12:59:05 [ExceptionHandler] Some errors occurred while generating GraphQL schema:
Input Object type Sgp_ch_turnos_agenteUpdateManyDataInput must define one or more fields.
```

that's my auto generated file:

```ts
import * as TypeGraphQL from "type-graphql";
import GraphQLJSON from "graphql-type-json";
import { JsonValue, InputJsonValue } from "@prisma/client";

@TypeGraphQL.InputType({
isAbstract: true,
description: undefined,
})
export class Sgp_ch_turnos_agenteUpdateManyDataInput {
}
```

Start by reproducing the issue with `npx prisma generate` and inspect the generated `Sgp_ch_turnos_agenteUpdateManyDataInput` class shown in the report. Trace how many-to-many relationship join tables produce this input type; done means generated input types define valid fields and Nest GraphQL schema generation no longer reports an empty input object.

Written by the indexing model from the issue text.