Upgrading docker images debian from version 12(bookworm) to 13(trixie).

### Description Bookworm regular support ended 11 Jul 2026; Airflow’s own policy is to switch ~6 months before that — so this is overdue by policy, even though Bookworm LTS runs to 2028. Trixie has been stable since Aug 2025 (~1 year). ### Use case/motivation I noticed 3 critical vulnerabilities related to the unbound package: CVE-2026-42960, CVE-2026-33278, CVE-2026-50252 that for bookworm have no upgrade. Would be much easier to jump forward with the version instead. ### Related issues _No response_ ### Are you willing to submit a PR? - [ ] Yes I am willing to submit a PR! ### Code of Conduct - [x] I agree to follow this project's [Code of Conduct](https://github.com/apache/airflow/blob/main/CODE_OF_CONDUCT.md)