Contradictory to GitHub API documentation, the "List Dependabot alerts for an organization" endpoint for all enterprise, organization, and repository no longer supports cursor pagination.
All list Dependabot endpoints return the following Link header:
Link: <https://api.github.com/organizations/myOrg/dependabot/alerts?page=1>; rel="next", <https://api.github.com/organizations/myOrg/dependabot/alerts?page=100>; rel="last"