Bump postgres from 14 to 16 in /compose/production/postgres

Bumps postgres from 14 to 16.

---
updated-dependencies:
- dependency-name: postgres
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

compose/production/postgres/Dockerfile

@@ -1,4 +1,4 @@
-FROM postgres:14
+FROM postgres:16
 
 COPY ./compose/production/postgres/maintenance /usr/local/bin/maintenance
 RUN chmod +x /usr/local/bin/maintenance/*