chore(pangolin): bump postgres 17.5 -> 17.11 (DEV-533)

Patch bump per DEV-520 plan. Only pangolin uses postgres:17.5*;
other apps (paperclip, directus, forgejo, stalwart) are on
postgres:16-alpine and are out of scope for this ticket.

Co-Authored-By: Paperclip <noreply@paperclip.ing>

apps/pangolin/pangolin-deployment.yaml

@@ -35,7 +35,7 @@ spec:
     spec:
       initContainers:
       - name: wait-for-postgres
-        image: postgres:17.5
+        image: postgres:17.11
         command:
         - /bin/sh
         - -c

apps/pangolin/postgres.yaml

@@ -57,7 +57,7 @@ spec:
         fsGroup: 999
       containers:
         - name: postgres
-          image: postgres:17.5
+          image: postgres:17.11
           imagePullPolicy: IfNotPresent
           ports:
             - containerPort: 5432