docker-compose PostgreSQL 16 (#5661)

https://www.postgresql.org/about/news/postgresql-16-released-2715/
Watch out, there are no auto-updates between major versions

Docker/freshrss/docker-compose-db.yml

@@ -6,7 +6,7 @@ volumes:
 services:
 
   freshrss-db:
-    image: postgres:15
+    image: postgres:16
     container_name: freshrss-db
     hostname: freshrss-db
     restart: unless-stopped