Only update documentation when merging into default branch

The new job to update the gitlab_templates documentation pages appears to be running on every scheduled pipeline. The intention was that it should only run when committing to the default branch, and also only when there are changes to the docs files. The job has

pages:
  rules:
    - if: $CI_COMMIT_BRANCH == $CI_DEFAULT_BRANCH
      changes:
        - docs/**/*
        - mkdocs.yml

but this does not seem to prevent the job running - see https://git.drupalcode.org/project/gitlab_templates/-/pipelines/128430

This issue also updates the Testing Merge Requests doc page - the preview is 3435899-pages-on-merge/docs/info/testing-mrs.md

Edited by drupalbot
To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information