Merge branch '425470-nightly-postgres-16-specs' into 'master'

Add Postgres 16 to nightly rspec builds

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/144933



Merged-by: Peter Leitzen <pleitzen@gitlab.com>
Approved-by: Peter Leitzen <pleitzen@gitlab.com>
Reviewed-by: Peter Leitzen <pleitzen@gitlab.com>
Co-authored-by: Jon Jenkins <jjenkins@gitlab.com>