title: Mapstruct ignore target nested property mapping
body: <p>I have following DTO and Domain objects. I am using Mapstruct to copy domain object to DTO object.</p>
  
  <pre><code>public class AddressDomain {
              private String street;
              private Telephone telephone;
      }
  public class CompanyDomain{
          private String id;
          private Address address;
  }
  
  public class AddressDTO {
              private String street;
              private Telephone telephone;
      }
  public class CompanyDTO{
          private String id;
          private Address address;
  }
  </code></pre>
  
  <p>Mapping Domain to DTO using below Mapper. i don't want to map <strong>telephone</strong> property from domain to DTO. How to do that? i tried providing nested target property in mapping ignore but it gives error:</p>
  
  <pre><code>public interface CompanyMapper {
      //**below line gives error**
      @Mapping(target = "address.telephone", ignore=true)
      CompanyDTO map(AddressDTO dto);
  }
  </code></pre>