Fix the field used for the Pinned Items last updated date

[chrisvogt]

The Last updated date seems suspicious and I don't think the correct field is being used because in this screenshot, both of these repos have had PRs merged in the last few days. One of them I updated the About section for the repository, and so I'm suspecting the field I'm using in my query – repository.updatedAt – might actually be when the GitHub Repository, like it's settings or About section, were last updated. I'll need to review the