Merge branch 'docs/bprescott/20231222-dbvers' into 'master'

Maximum supported PostgreSQL version

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/140555



Merged-by: Diogo Frazão <dfrazao@gitlab.com>
Approved-by: Diogo Frazão <dfrazao@gitlab.com>
Co-authored-by: Amy Qualls <aqualls@gitlab.com>
Co-authored-by: Ben Prescott <bprescott@gitlab.com>