build(deps): bump postgres in /Containers/postgresql

Bumps postgres from 18.3-alpine to 18.4-alpine.

---
updated-dependencies:
- dependency-name: postgres
  dependency-version: 18.4-alpine
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Containers/postgresql/Dockerfile

@@ -1,6 +1,6 @@
 # syntax=docker/dockerfile:latest
 # From https://github.com/docker-library/postgres/blob/master/18/alpine3.23/Dockerfile
-FROM postgres:18.3-alpine
+FROM postgres:18.4-alpine
 
 ENV PGDATA=/var/lib/postgresql/data