[proposal] Optional pointer return in unmarshalInput

[LuciferInLove]

What happened?

It'd be nice to have an option to return a pointer instead of a value in unmarshalInput:
https://github.com/99designs/gqlgen/blob/master/codegen/input.gotpl#L3

What did you expect?

I'd expect something like:
codegen/input.gotpl

func (ec *executionContext) unmarshalInput{{ .Name }}(ctx context.Context, obj interface{}) ({{ if returnPointerInUnmarshalInput }}*{{ end }}{{.Type | ref}}, error) {
...
return {{ if returnPointerInUnmarshalInput }}&{{ end }}it, nil

And related changes in codegen/type.gotpl.
https://github.com/99designs/gqlgen/blob/master/codegen/type.gotpl#L78

Minimal graphql.schema and models to reproduce

versions

• go run github.com/99designs/gqlgen version? v0.17.16
• go version? go1.18.6