Auto DevOps rollout is not compatible with Kubernetes 1.16

On Kubernetes 1.16, the rollout 50% job (https://staging.gitlab.com/hello-staging/minimal-ruby-app/-/jobs/37098908) fails with:

 deployment "production-rollout" successfully rolled out
 $ auto-deploy scale stable $((100-ROLLOUT_PERCENTAGE))
 UPGRADE FAILED
 Error: unable to recognize "": no matches for kind "Deployment" in version "extensions/v1beta1"
 Error: UPGRADE FAILED: unable to recognize "": no matches for kind "Deployment" in version "extensions/v1beta1"
 ERROR: Job failed: exit code 1

Even though we have the right env vars to use apps/v1.

Root cause

The scale function is using helm upgrade --reuse-values, see #209045 (comment 422968926) for details on why this breaks things