Update metadata assignment

Update group/stage assignment in metadata.

doc/ci/lint.md

 ---
-stage: none
-group: unassigned
+stage: Verify
+group: Pipeline Authoring
 info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#assignments
 ---
 <!-- markdownlint-disable MD044 -->