Bump postgres from 17.5 to 17.6 in /tooling/docker

Bumps postgres from 17.5 to 17.6.

---
updated-dependencies:
- dependency-name: postgres
  dependency-version: '17.6'
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

tooling/docker/postgresql.Dockerfile

@@ -1,3 +1,3 @@
 # PostgreSQL
 # See https://hub.docker.com/_/postgres
-FROM docker.io/postgres:17.5
+FROM docker.io/postgres:17.6