Update postgres:18.3-alpine Docker digest from 18.3 to 18.3-alpine (docker-compose.yml)

Author: renovate[bot]

docker-compose.yml

@@ -120,7 +120,7 @@ services:
           source: ./docker/extra_settings
           target: /app/docker/extra_settings
   postgres:
-    image: postgres:18.3-alpine@sha256:4da1a4828be12604092fa55311276f08f9224a74a62dcb4708bd7439e2a03911
+    image: postgres:18.3-alpine@sha256:54451ecb8ab38c24c3ec123f2fd501303a3a1856a5c66e98cecf2460d5e1e9d7
     environment:
       PGDATA: /var/lib/postgresql/data
       POSTGRES_DB: ${DD_DATABASE_NAME:-defectdojo}