add HalResponse.toVoidEntity() for responses without body

Author: NielsCW

src/main/java/com/contentgrid/hateoas/client/hal/HalResponse.java

@@ -2,12 +2,15 @@
 
 import java.util.Objects;
 import org.springframework.http.ResponseEntity;
-import org.springframework.lang.Nullable;
 
 public interface HalResponse {
 
     <T> ResponseEntity<T> toEntity(Class<T> bodyType);
 
+    default ResponseEntity<Void> toVoidEntity() {
+        return this.toEntity(Void.class);
+    }
+
     default ResponseEntity<HalDocument> toHalEntity() {
         return this.toEntity(HalDocument.class);
     }