Updated Drupal to 8.6. This goes with the following updates because it's possible...

[yaffs-website] / web / core / modules / user / user.info.yml

name: User
type: module
description: 'Manages the user registration and login system.'
package: Core
version: VERSION
core: 8.x
required: true
configure: user.admin_index
dependencies:
  - drupal:system