chore(deps): update postgres docker tag to v18

renovate.json

@@ -3,6 +3,7 @@
   "extends": [
     "config:recommended", // Included in config:best-practices anyway, but added for clarity.
     "config:best-practices",
+    "schedule:daily",
     ":ignoreUnstable"
   ],
   "packageRules": [
@@ -19,10 +20,5 @@
         "patch"
       ]
     }
-  ],
-  "docker-compose": {
-    "managerFilePatterns": [
-      "/(^|/)(?:docker-)?compose[^/]*\\.ya?ml.j2$/"
-    ]
-  }
+  ]
 }

resources/chaosknoten/keycloak/docker_compose/compose.yaml.j2

@@ -46,7 +46,7 @@ services:
       - "8080:8080"
 
   db:
-    image: postgres:18.0@sha256:b5b154cfe5bfed10a2e68f9d064ab76cebf28b4c80bedf714e6b500f839fbe9d
+    image: postgres:15.14
     restart: unless-stopped
     networks:
       - keycloak