fix: remove checkout step in mergeability check

[upsuper]

Changes

Based on tj-actions/changed-files's README, checkout files in advance isn't necessary. I suspect the extra checkout step may be the cause of errors like https://github.com/withastro/astro/actions/runs/18036175690/job/51485929418?pr=14441

Testing

Change to GitHub workflow.

Docs

Bug fix for GitHub workflow, no effect on any package.

[changeset-bot]

⚠️ No Changeset found

Latest commit: 6a47301

Merging this PR will not cause a version bump for any packages. If these changes should not result in a new version, you're good to go. If these changes should result in a version bump, you need to add a changeset.

Click here to learn what changesets are, and how to add one.

Click here if you're a maintainer who wants to add a changeset to this PR

[delucis]

I think we can try this and see if it works 👍

The changed-files action docs mention “A maximum of 3000 files can be returned” but that seems like a pretty high limit, so not sure we’re that likely to hit it.

Could you update branch as well? Or give us permissions to edit this PR?

[upsuper]

Could you update branch as well?

What do you mean by updating branch? I've committed the change you suggested.

Or give us permissions to edit this PR?

I do want to and I thought it was always enabled until I realized that a PR created from a fork in an org can't grant that permission currently (see a relevant discussion). I may need to revisit how I manage all the forks.

[upsuper]

I see what do you mean by update branch. I've hit the button to merge in main.

[delucis]

Perfect — thanks @upsuper! I’ll merge and we can see if it works 🙂

[delucis]

Updated branch in a PR to test it and seemed to work OK! https://github.com/withastro/astro/actions/runs/18523453176/job/52788590688?pr=14541