docs/data/reusables/webhooks/pull_request_webhook_properties.md

Key	Type	Description
action	string	The action that was performed. Can be one of opened, edited, closed, assigned, unassigned, review_requested, review_request_removed, ready_for_review, converted_to_draft, labeled, unlabeled, synchronize, locked, unlocked, or reopened. If the action is closed and the merged key is false, the pull request was closed with unmerged commits. If the action is closed and the merged key is true, the pull request was merged.