Test using PostgreSQL 11 with the GitLab chart
Summary
PostgreSQL 11 was added to Omnibus in %12.8 and will become the minimum required Postgres version by GitLab 13.0. Although we recommend that GitLab chart installs use an external Postgres database, we do include Postgres with the chart install for testing purposes. We should update the chart to support using PG11.
Proposal
It is already possible to set a version flag to install PG11 with the chart. We should test and validate that this works as expected.