Warn message that MiniKube installer is from an Unknown Publisher

[indcoder]

Is this a BUG REPORT or FEATURE REQUEST? (choose one):
BUG REPORT

Minikube version (use minikube version):

0.11.0
Environment:

• OS (e.g. from /etc/os-release): Windows 10 Pro
• VM Driver (e.g. cat ~/.minikube/machines/minikube/config.json | grep DriverName):
• Docker version (e.g. docker -v):
• Install tools: Windows Installer
• Others:

What happened:
When clicking on the windows installer, Windows warns user that the installer is from an "Unknown Publisher""

What you expected to happen:
The installer should be securely signed with either Kubernetes or CNCF certificate so that Windows does not show the warning message when clicking it.

How to reproduce it (as minimally and precisely as possible):
Click on the windows installer after it has downloaded it

Anything else do we need to know:

[fejta-bot]

Issues go stale after 30d of inactivity.
Mark the issue as fresh with /remove-lifecycle stale.
Stale issues rot after an additional 30d of inactivity and eventually close.

Prevent issues from auto-closing with an /lifecycle frozen comment.

If this issue is safe to close now please do so with /close.

Send feedback to sig-testing, kubernetes/test-infra and/or @fejta.
/lifecycle stale

[fejta-bot]

Stale issues rot after 30d of inactivity.
Mark the issue as fresh with /remove-lifecycle rotten.
Rotten issues close after an additional 30d of inactivity.

If this issue is safe to close now please do so with /close.

Send feedback to sig-testing, kubernetes/test-infra and/or @fejta.
/lifecycle rotten
/remove-lifecycle stale

[fejta-bot]

Rotten issues close after 30d of inactivity.
Reopen the issue with /reopen.
Mark the issue as fresh with /remove-lifecycle rotten.

Send feedback to sig-testing, kubernetes/test-infra and/or fejta.
/close