Update price for 100 users on Docker Hub after pricing change (2020)

Updates price for 100 users on Docker Hub after pricing change (2020). Updates !7218 (merged) (%10.4)

Why is this change being made?

Docker, Inc. changed its subscriptions on 2020-05-14 and then Container Registry feature in GitLab Premium is equivalent to Docker Pro Subscriptions.

First five members is $25, $7 per additional team member

Third-party public note: docker/roadmap#92

Effective at https://about.gitlab.com/calculator/roi/replace/

Author Checklist

• Provided a concise title for the MR
• Added a description to this MR explaining the reasons for the proposed change, per say-why-not-just-what
• Assign this change to the correct DRI
  • If the DRI for the page/s being updated isn’t immediately clear, then assign it to one of the people listed in the "Maintained by" section in on the page being edited.
  • If your manager does not have merge rights, please ask someone to merge it AFTER it has been approved by your manager in #mr-buddies.
  • If the changes relate to any part of the project other than updates to content and/or data files please make sure to ping @gl-static-site-editor in a comment for a review and merge. For example changes to .gitlab-ci.yml, JavaScript/CSS/Ruby code or the layout files. (this requirement has been removed pending identification of a new DRI for the handbook)