Automatic merge from submit-queue
Update images that use ubuntu-slim base image to :0.6
**What this PR does / why we need it**: `ubuntu-slim:0.4` is somewhat old, being based on Ubuntu 16.04, whereas `ubuntu-slim:0.6` is based on Ubuntu 16.04.1.
**Special notes for your reviewer**: I haven't pushed any of these images yet, so I expect all of the e2e builds to fail. If we're happy with the changes, I can push the images and then re-trigger tests.
**Release note**:
```release-note
NONE
```
cc @aledbf as FYI
Deprecation Notice: This directory has entered maintenance mode and will not be accepting new providers. Please submit new automation deployments to kube-deploy. Deployments in this directory will continue to be maintained and supported at their current level of support.
The scripts and data in this directory automate creation and configuration of a Kubernetes cluster, including networking, DNS, nodes, and master components.