net/traefik: Update to upstream version 2.9.4

Details:
- Update to 2.9.x branch:
  https://github.com/traefik/traefik/releases/tag/v2.9.4
- No breaking config changes, see
  https://doc.traefik.io/traefik/migration/v2/#v29
- but "Traefik Pilot" has been removed.

MFH:		2022Q4