Update Docker build for terrascan to use numeric UID

[jlk]

• terrascan version: 1.5.0
• Operating System: MacOS

Description

When developing helm chart, to follow best practices I'd like to set a securityContext of runAsNonRoot: true
Unfortunately, when the k8s deployment creates a pod, the following error is seen in pod details:

Events:
  Type     Reason     Age               From               Message
  ----     ------     ----              ----               -------
  Normal   Scheduled  13s               default-scheduler  Successfully assigned default/terrahook-7b8fd679ff-jsk5k to aks-agentpool-30212186-vmss000002
  Normal   Pulling    13s               kubelet            Pulling image "alpine/git"
  Normal   Pulled     12s               kubelet            Successfully pulled image "alpine/git"
  Normal   Created    12s               kubelet            Created container git-cloner
  Normal   Started    12s               kubelet            Started container git-cloner
  Normal   Pulled     9s (x2 over 10s)  kubelet            Container image "accurics/terrascan:1.5.0" already present on machine
  Warning  Failed     9s (x2 over 10s)  kubelet            Error: container has runAsNonRoot and image has non-numeric user (terrascan), cannot verify user is non-root

So looks like we need to change the Dockerfile to read

USER 101

[Rchanger]

We can also set runAsUser field in helm configurations.

 runAsUser: 101