Upgrades PreProd to Helm3

John Jarvisrequested to merge
jarv/helm3-poc into master

What does this MR do?

This sets USE_HELM3 for preprod so we use helm3 for the gitlab release.

the conversion of helm2->helm3 was done locally with:

helm3 2to3 convert --tiller-out-cluster gitlab
Edited by John Jarvis

Merge request reports