Prep for the 1.16.0 release

[sawagh]

What type of PR is this?

/kind release

What this PR does / Why we need it:

Which issue(s) this PR fixes:

Closes #2126

Special notes for your reviewer:

[agones-bot]

Build Succeeded 👏

Build Id: 20e6fda5-2d3a-4974-8293-3c3fb5398ff2

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

• image: gcr.io/agones-images/agones-controller:1.16.0-dc47c1a
• image: gcr.io/agones-images/agones-ping:1.16.0-dc47c1a
• Linux C++ SDK (build): agonessdk-1.16.0-dc47c1a-linux-arch_64.tar.gz
• SDK Server: agonessdk-server-1.16.0-dc47c1a.zip

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

• https://dc47c1a-dot-preview-dot-agones-images.appspot.com/

To install this version:

• git fetch https://github.com/googleforgames/agones.git pull/2130/head:pr_2130 && git checkout pr_2130
• helm install ./install/helm/agones --namespace agones-system --name agones --set agones.image.tag=1.16.0-dc47c1a

[google-oss-robot]

[APPROVALNOTIFIER] This PR is APPROVED

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

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 [roberthbailey]

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