Website: Update API docs to Kubernetes 1.16

[aLekSer]

Recurrent task is to update template value, used in
make gen-api-docs.

What type of PR is this?

/kind documentation

What this PR does / Why we need it:

Which issue(s) this PR fixes:
Work on #1649

Special notes for your reviewer:

[agones-bot]

Build Succeeded 👏

Build Id: d8566b27-fd2a-47ff-afb0-49c965e4f17c

The following development artifacts have been built, and will exist for the next 30 days:

• image: gcr.io/agones-images/agones-controller:1.9.0-5117c3f
• image: gcr.io/agones-images/agones-sdk:1.9.0-5117c3f
• image: gcr.io/agones-images/agones-ping:1.9.0-5117c3f
• Linux C++ SDK (build): agonessdk-1.9.0-5117c3f-linux-arch_64.tar.gz
• SDK Server: agonessdk-server-1.9.0-5117c3f.zip

A preview of the website (the last 30 builds are retained):

• https://5117c3f-dot-preview-dot-agones-images.appspot.com/

To install this version:

• git fetch https://github.com/googleforgames/agones.git pull/1814/head:pr_1814 && git checkout pr_1814
• helm install ./install/helm/agones --namespace agones-system --name agones --set agones.image.tag=1.9.0-5117c3f

[google-oss-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: aLekSer, roberthbailey

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• OWNERS [aLekSer,roberthbailey]

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