Update yq command in operator instructions (#488)
Update yq command in operator instructions (#488)

The yq tool referenced in the operator deployment instructions
recently moved to v4, where commands from previous versions are not supported.
This commit updates the 'yq w ..' command to 'yq eval ..'  supported by v4.
Reference: https://mikefarah.gitbook.io/yq/v/v4.x/upgrading-from-v3#updating-writing-documents
kubeflow/kfctl,kubeflow/kfctl,kubeflow/kfctl