net/traefik: Update to upstream release 3.6.7
Details:
- Bugfix release, see https://github.com/traefik/traefik/releases/tag/v3.6.7
- Addresses a potential DoS vulnerability, see https://github.com/traefik/traefik/security/advisories/GHSA-cwjm-3f7h-9hwq
- This may require an update to the traefik configuration: https://doc.traefik.io/traefik/v3.6/migrate/v3/#v367
MFH: 2026Q1
Security: CVE-2026-22045
(cherry picked from commit a18d213f915268dbb7346b8ff1550ed418c3afff)