Remove warnings due serialization withou id.

src/main/java/koz01/java2/lab10/TeachingStaff.java

@@ -9,6 +9,8 @@ import lombok.Setter;
 @NoArgsConstructor
 public class TeachingStaff extends Staff {
 
+	private static final long serialVersionUID = 1L;
+
 	@Getter
 	@Setter
 	private String qualification;