Replaces the duplicated Renovate config with a simple extend from the
org-level preset (privilegedescalation/.github:renovate-config). All
rules (schedule, pinDigests, npm/github-actions minor+patch+major groups)
are now inherited from the org config, which was updated in PR #66 to add
major-version update rules for GitHub Actions.
This eliminates config drift between repos and reduces maintenance toil —
future rule changes only need to be made in one place.
Co-Authored-By: Paperclip <noreply@paperclip.ing>