public @This @NonNull Builder<C, T> optional(final @Nullable DefaultValue<? super C, T> defaultValue) {
            return this.optional().defaultValue(defaultValue);
        }
Sets {@code required} to {@code true} and updates the {@code defaultValue}.

@param defaultValue the default value
@return {@code this}
cloud-core/src/main/java/org/incendo/cloud/component/CommandComponent.java