Geo PostgreSQL specs should test against 9.6 & 10.7
I noticed that geo-postgresql_spec.rb
failed miserably when I attempted to bump the PostgreSQL version from 9.2 to 9.6: https://gitlab.com/gitlab-org/omnibus-gitlab/-/jobs/53962171
Since we require Geo users to use 9.6, we should test against that.
Proposal
Move all Geo specs in spec/chef/gitlab-ee/recipes/geo-postgresql_spec.rb
to shared examples, and run all those tests with PG 9.6 and 10.7.
This would clean up the ~Geo part of #2922 (closed).