Support running as non-root, on a high port

Hi everyone,

We use mcr.microsoft.com/azure-functions/dotnet:3.0 to implement function apps via [KEDA](https://docs.microsoft.com/en-us/azure/azure-functions/functions-kubernetes-keda), and we want to run all of our containers with Azure's "Kubernetes cluster pod security restricted standards for Linux-based workloads" policy. This means we need both to run as non-root, and to disallow privilege escalation via setcap. Could you please consider adding this capability?

Thanks,
Paul