Bump kubesec's packaged helm version to latest

Proposal

Our kubesec analyzer currently ships with helm in order to compile user's k8s manifests easily for Category:SAST scanning.

The current helm version is listed as 3.4.2. This is quite old as the latest version is 3.8.0 (as of this writing). We should bump to the latest.

I'm unsure how stable helm minor releases are, so in this process we should ensure we are not introducing an significant breaking changes or regressions in doing so.