This commit introduces a new command, `minikube tunnel`, a LoadBalancer emulator functionality, that must be run with root permissions.

This command:

* Establishes networking routes from the host into the VM for all IP ranges used by Kubernetes.
* Enables a cluster controller that allocates IPs to services external `LoadBalancer` IPs.
* Cleans up routes and IPs when stopped (Ctrl+C), when `minikube` stops, and when `minikube tunnel` is ran with the `--cleanup` flag

Upgrade Docker, from 17.12.1-ce to 18.06.1-ce

Introduces hack/boilerplate/fix.sh that automatically fixes the copyright header in files. 

Remove scary temporary non-failures so that they do not distract from real ones

Update releases.json to v0.30.0

v0.30.0 release notes

Docker >= 18.06 is needed for securityContext.procMount (Kubernetes >= 1.12)

See kubernetes/kubernetes#64283 and docker/docker-ce@67fe100
Signed-off-by: NAkihiro Suda <suda.akihiro@lab.ntt.co.jp>

Bump Makefile to v0.30.0

Initial support for Kubernetes 1.12+

Add scripts to generate release notes.

Output the gofmt diff as well as the affected files.

Use "kubectl proxy" instead of a NodePort to expose the dashboard.

Remove refs to k8s_releases.json now that `get-k8s-versions` is gone.

NOTE: This differs against what 1.11 would do, but matches our current
Travis CI configuration.

It is otherwise difficult to debug issues when a contributors gofmt
version differs from the one Travis uses.

This allows us to always test against the latest stable release without
editing this file every 6 months.

It is otherwise difficult to debug issues when a contributors gofmt
version differs from the one Travis uses.