Add an extra step to the kubernetes upgrade tasks.

[roberthbailey]

What type of PR is this?

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/kind breaking
/kind bug
/kind cleanup

/kind documentation

/kind feature
/kind hotfix

What this PR does / Why we need it: Add an extra step to the k8s upgrade tasks so that we keep the image used for uninstall up to date. We had been using one that was very old (prior to #2615) and we should use one that is at the same version as the version of Kubernetes that we support to ensure maximum compatibility.

Which issue(s) this PR fixes:

Special notes for your reviewer:

[google-oss-prow]

[APPROVALNOTIFIER] This PR is APPROVED

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

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• OWNERS [markmandel,roberthbailey]

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[agones-bot]

Build Succeeded 👏

Build Id: 0201d29e-f78f-4f2f-b25a-7c22eec62d76

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

• image: gcr.io/agones-images/agones-controller:1.24.0-79c5670-amd64
• image: gcr.io/agones-images/agones-controller:1.24.0-79c5670-arm64
• image: gcr.io/agones-images/agones-ping:1.24.0-79c5670-amd64
• image: gcr.io/agones-images/agones-ping:1.24.0-79c5670-arm64
• Linux C++ SDK (build): agonessdk-1.24.0-79c5670-arm64-linux-arch_64.tar.gz
• SDK Server: agonessdk-server-1.24.0-79c5670-arm64.zip

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

• https://79c5670-dot-preview-dot-agones-images.appspot.com/

To install this version:

• git fetch https://github.com/googleforgames/agones.git pull/2616/head:pr_2616 && git checkout pr_2616
• helm install agones ./install/helm/agones --namespace agones-system --set agones.image.tag=1.24.0-79c5670-amd64