Fix doc for multiple k8s version support

[gongmax]

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/kind breaking
/kind bug
/kind cleanup

/kind documentation

/kind feature
/kind hotfix

What this PR does / Why we need it:

Which issue(s) this PR fixes:

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Special notes for your reviewer:

[agones-bot]

Build Succeeded 👏

Build Id: e77acd5f-9622-48ed-b558-fbb7f193e30e

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

• image: us-docker.pkg.dev/agones-images/ci/agones-controller:1.31.0-9214ff1-amd64
• image: us-docker.pkg.dev/agones-images/ci/agones-sdk:1.31.0-9214ff1-linux-amd64
• image: us-docker.pkg.dev/agones-images/ci/agones-ping:1.31.0-9214ff1-amd64
• image: us-docker.pkg.dev/agones-images/ci/agones-allocator:1.31.0-9214ff1-amd64
• Linux C++ SDK (build): agonessdk-1.31.0-9214ff1-amd64-linux-arch_64.tar.gz
• SDK Server: agonessdk-server-1.31.0-9214ff1-amd64.zip

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

• https://9214ff1-dot-preview-dot-agones-images.appspot.com/

To install this version:

• git fetch https://github.com/googleforgames/agones.git pull/3038/head:pr_3038 && git checkout pr_3038
• helm install agones ./install/helm/agones --namespace agones-system --agones.image.release=us-docker.pkg.dev/agones-images/ci --set agones.image.tag=1.31.0-9214ff1-amd64

[agones-bot]

Build Succeeded 👏

Build Id: 84514258-d340-4891-86ba-714d71bd440a

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

• image: us-docker.pkg.dev/agones-images/ci/agones-controller:1.31.0-de77f29-amd64
• image: us-docker.pkg.dev/agones-images/ci/agones-sdk:1.31.0-de77f29-linux-amd64
• image: us-docker.pkg.dev/agones-images/ci/agones-ping:1.31.0-de77f29-amd64
• image: us-docker.pkg.dev/agones-images/ci/agones-allocator:1.31.0-de77f29-amd64
• Linux C++ SDK (build): agonessdk-1.31.0-de77f29-amd64-linux-arch_64.tar.gz
• SDK Server: agonessdk-server-1.31.0-de77f29-amd64.zip

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

• https://de77f29-dot-preview-dot-agones-images.appspot.com/

To install this version:

• git fetch https://github.com/googleforgames/agones.git pull/3038/head:pr_3038 && git checkout pr_3038
• helm install agones ./install/helm/agones --namespace agones-system --agones.image.release=us-docker.pkg.dev/agones-images/ci --set agones.image.tag=1.31.0-de77f29-amd64

[google-oss-prow]

New changes are detected. LGTM label has been removed.

[google-oss-prow]

[APPROVALNOTIFIER] This PR is APPROVED

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

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[agones-bot]

Build Failed 😱

Build Id: 232fc264-fbbd-47a3-87e7-9262a198f7b9

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• Cloud Build log download

To get permission to view the Cloud Build view, join the agones-discuss Google Group.

[agones-bot]

Build Failed 😱

Build Id: 6afb2bf6-5caa-49ef-9d32-9ff608769287

• Cloud Build view
• Cloud Build log download

To get permission to view the Cloud Build view, join the agones-discuss Google Group.

[agones-bot]

Build Succeeded 👏

Build Id: 4dcc5d61-6706-45b8-b8e9-9034b08be50d

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

• image: us-docker.pkg.dev/agones-images/ci/agones-controller:1.31.0-41fd35e-amd64
• image: us-docker.pkg.dev/agones-images/ci/agones-sdk:1.31.0-41fd35e-linux-amd64
• image: us-docker.pkg.dev/agones-images/ci/agones-ping:1.31.0-41fd35e-amd64
• image: us-docker.pkg.dev/agones-images/ci/agones-allocator:1.31.0-41fd35e-amd64
• Linux C++ SDK (build): agonessdk-1.31.0-41fd35e-amd64-linux-arch_64.tar.gz
• SDK Server: agonessdk-server-1.31.0-41fd35e-amd64.zip

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

• https://41fd35e-dot-preview-dot-agones-images.appspot.com/

To install this version:

• git fetch https://github.com/googleforgames/agones.git pull/3038/head:pr_3038 && git checkout pr_3038
• helm install agones ./install/helm/agones --namespace agones-system --agones.image.release=us-docker.pkg.dev/agones-images/ci --set agones.image.tag=1.31.0-41fd35e-amd64