Interface implementing interface does not generate correct code (Version: 4.0.1)

[MLNW]

Issue Description

When I create an interface that implements another interface like so:

interface Node {
    id: ID!
}

interface Origin implements Node {
    id: ID!
}

The resulting model does not correctly extend the parent interface.

Steps to Reproduce

• Add two interfaces
• Extend second interface with first
• Generate code
• Check the result

Expected Result

public interface OriginTO extends NodeTO {

    @javax.validation.constraints.NotNull
    String getId();

}

Actual Result

public interface OriginTO {

    @javax.validation.constraints.NotNull
    String getId();

}

Your Environment and Setup

• graphql-java-codegen: 4.0.1
• Build tool: Gradle
• Java tool: 15.0.1

Additional context

Support for interfaces implementing other interfaces has only recently been added to graphql: graphql/graphql-spec#373

[MLNW]

Thank you very much for the quick response!