Eliminate JITServer Helm Chart warning about beta.kubernetes.io/arch

[mpirvu]

When deploying JITServer with the helm chart I see the following warning

W0513 13:23:01.453840   84779 warnings.go:70] spec.template.spec.affinity.nodeAffinity.requiredDuringSchedulingIgnoredDuringExecution.nodeSelectorTerms[0].matchExpressions[0].key: beta.kubernetes.io/arch is deprecated since v1.14; use "kubernetes.io/arch" instead

We should make the suggested change to eliminate the warning.