Create proposal for Praefect server upgrades

Overview

In &862 (closed) we want to upgrade the Praefect proxy ubuntu version from 16.04 to 20.04. Write down a proposal on how to do this, and the outcome should be that we update the epic with the proposal.

Action Items

• Decide if we should change machine type part of the upgrade 👉 https://gitlab.com/gitlab-com/gl-infra/reliability/-/issues/17102#note_1237595243
  • We'll change the machine type to t2d-standrd-8
  • We expected some cost savings https://gitlab.com/gitlab-com/gl-infra/reliability/-/issues/17102#note_1241795028
• Detailed and manual walk-through on how to do the upgrade 👉 https://gitlab.com/steveazz/praefect-upgrade-poc