feat: add support for Kubernetes v1.15.0-alpha.1

[mboersma]

Reason for Change:

See https://github.com/kubernetes/kubernetes/blob/master/CHANGELOG-1.15.md#v1150-alpha1

Issue Fixed:

Requirements:

• Windows artifacts uploaded to acsmirror blob store
• uses conventional commit messages
• includes documentation
• adds unit tests
• tested upgrade from previous version

Notes:

[codecov]

Codecov Report

Merging #1140 into master will increase coverage by 0.04%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master    #1140      +/-   ##
==========================================
+ Coverage   74.71%   74.76%   +0.04%     
==========================================
  Files         129      129              
  Lines       18387    18422      +35     
==========================================
+ Hits        13738    13773      +35     
  Misses       3856     3856              
  Partials      793      793

[zhiweiv]

Metrics server 0.3.x doesn’t work with Windows nodes, see kubernetes/kubernetes#75934.

Besides, the parameters are changed in 0.3.x, you should update the kubernetesmasteraddons-metrics-server-deployment.yaml.

[mboersma]

update the kubernetesmasteraddons-metrics-server-deployment.yaml

Let's do that as a separate task: #1172.

[jackfrancis]

/lgtm

[acs-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: jackfrancis, mboersma

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• OWNERS [jackfrancis,mboersma]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment