feat: Port Auto Deploy to Helm 3

BREAKING CHANGE: The move to Helm 3 is a breaking change. Deploying to
namespaces with existing Helm 2 releases is not supported. Those first
need to be migrated to Helm 3 using a tool like helm-2to3. See
https://github.com/helm/helm-2to3 for more info.

BREAKING CHANGE: The Helm 3 CLI itself has several breaking changes,
so CI job scripts may need to be upgraded.