chore(deps): update docker.io/library/postgres docker tag to v18 (#1498)

* chore(deps): update docker.io/library/postgres docker tag to v18

* chore: sync template versions with image updates

---------

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>
Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>

library/compose/postgres/compose.yaml.j2

@@ -1,6 +1,6 @@
 services:
   {{ service_name }}:
-    image: docker.io/library/postgres:17.6
+    image: docker.io/library/postgres:18.1
     {#
       If not in swarm mode, apply restart policy and container_name,
       else swarm mode handles restarts via deploy.restart_policy

library/compose/postgres/template.yaml

@@ -16,9 +16,9 @@ metadata:
     Documentation: https://www.postgresql.org/docs/
 
     GitHub: https://github.com/postgres/postgres
-  version: 17.6
+  version: 18.1
   author: Christian Lempa
-  date: '2025-09-28'
+  date: '2025-12-11'
   tags:
     - swarm
   draft: true