Test plan for deprecating TLS 1.0/1.1 and moving to TLS 1.2 in GitLab.com

Introduction

This test plan is for https://gitlab.com/gitlab-com/gl-security/engineering/issues/202

Test Plan

Run automated QA tests against a TLS 1.2 enabled environments.

The QA tests currently run on staging every 24 hours and enabling TLS 1.2 there would mean we are automatically covered. Until then, we can run the test agains any other environment (e.g. Canary) where TLS 1.2 is enabled.