validate default values in InputObjectTypes

[bhavinshah7]

Validate if the default values confirm to the NamedType defined in InputObjectTypes.

InputValueDefinition : desc=StringValue? name=Name ':' namedType=NamedType ('=' defaultValue=Value)? directives+=Directive* (',')?;

Other validations for reference

Add to an existing validation class or link a new validation here

similar validation in graphql-java

[jainrocks]

@ashpak-shaikh I can take this

[ashpak-shaikh]

Sure