Create a script to update some of the docker images in the prototypes (…

…kubeflow#1063)

* Add instructions to the releasing guide.

releasing/update_images.sh

@@ -0,0 +1,12 @@
+#!/bin/bash
+#
+# A script to automate updating the images to use in the ksonnet
+# components
+set -ex
+DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
+ROOT_DIR="$( cd ${DIR}/.. && pwd )"
+
+# Update the TFJob operator image
+python scripts/update_prototype.py \
+	--file=${ROOT_DIR}/kubeflow/core/prototypes/all.jsonnet \
+	--values=tfJobImage=gcr.io/kubeflow-images-public/tf_operator:v0.2.0