Add multi-version upgrade migration test for PG13

What does this MR do and why?

Add multi-version upgrade migration test for PG13. This enables to catch migration issues against minimum PG version supported by GitLab - PG13 until 17.0.

The job allows to catch errors like gitlab-org/quality/quality-engineering/team-tasks#2546 (comment 1834748456), when MR introduces migration which uses PG14 functions. The error was caught by GitLab QA job since Omnibus was still on PG13. The addition of multi-version upgrade with PG13 would allow to shift left on errors like this.

Full context - gitlab-org/quality/quality-engineering/team-tasks#2546 (comment 1834748456)

MR acceptance checklist

Please evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

How to set up and validate locally

1. Prepare GitLab env with PG13
2. Run multi-version upgrade test against GitLab with PG13 https://gitlab.com/gitlab-org/quality/pg-dump-generator#migration-upgrade-testing

Validation

CI config change was validated in !148090 (closed) - PG 14 passes https://gitlab.com/gitlab-org/gitlab/-/jobs/6494380658, PG13 fails https://gitlab.com/gitlab-org/gitlab/-/jobs/6494380666 as expected ✅

✅ With fix for PG13 in place - the job is passing now as well https://gitlab.com/gitlab-org/gitlab/-/jobs/6546131283