Update URLs for !reference tags in /releases

Why is this change being made?

The links have been dead after !72646 (merged) (%14.5) from https://about.gitlab.com/releases/2021/02/22/gitlab-13-9-released/#select-cicd-configuration-from-any-job-and-reuse-it and https://about.gitlab.com/releases/2021/09/22/gitlab-14-3-released/#support-merging-cicd-rules-arrays-with-reference.

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
  • Copy/paste the Slack conversation to document it for later, or upload screenshots. Verify that no confidential data is added.
• Assign reviewers for this change to the correct DRI(s)
  • 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.
• [n/a] If the changes affect team members, or warrant an announcement in another way, please consider posting an update in #whats-happening-at-gitlab linking to this MR.
  • If this is a change that directly impacts the majority of global team members, it should be a candidate for #company-fyi. Please work with internal communications and check the handbook for examples.