Update Dockerfile with different url for kubeflow

Dockerfile

@@ -2,7 +2,7 @@ ARG BASE_REGISTRY=registry1.dso.mil
 ARG BASE_IMAGE=ironbank/opensource/alpinelinux/alpine
 ARG BASE_TAG=3.20.2
 
-FROM docker.io/kubeflow/spark-operator:2.0.0-rc.0 as base
+FROM hub.docker.com/r/kubeflow/spark-operator:2.0.0-rc.0 as base
 FROM apache/spark:3.5.2 as spark
 
 FROM ${BASE_REGISTRY}/${BASE_IMAGE}:${BASE_TAG}