Create a major release page for the 6.0 version of the chart
Summary
Create a release page similar to the 5.0 landing page for the chart: https://gitlab.com/gitlab-org/charts/gitlab/-/blob/master/doc/releases/5_0.md
In this page we can include a reminder that PG13 is now the recommended version, but that PG12 is still support. Users do not need to do the database upgrade during the major release, but the landing page is a good opportunity to remind folks that they can start planning an upgrade to PG13
Edited by DJ Mountney