Add an image for updated postgresql-client

I am trying to bring PostgreSQL to CE/EE tests, the attempt is located at https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/10156

And I hit into https://gitlab.com/gitlab-org/gitlab-ce/builds/12814061

pg_dump: server version: 9.6.2; pg_dump version: 9.4.10
pg_dump: aborting because of server version mismatch
Backup failed

My first attempt is updating in the image, which failed at https://gitlab.com/gitlab-org/gitlab-ce/builds/12831435

/bin/bash: line 69: add-apt-repository: command not found

Perhaps we should just update the image, so here it is.