ObjectMeta should use additionalProperties

[markmandel]

What type of PR is this?

Uncomment only one /kind <> line, hit enter to put that in a new line, and remove leading whitespace from that line:

/kind breaking
/kind bug

/kind cleanup

/kind documentation
/kind feature
/kind hotfix

What this PR does / Why we need it:

Rather than using x-kubernetes-preserve-unknown-fields which allows both keys and values of any type, we should use additionalProperties which only allows a specified type (in this case "string") for keys and values.

Which issue(s) this PR fixes:

N/A

Special notes for your reviewer:

Better validation!

Also matches ObjectMeta's actual OpenAPI v2 spec.

[agones-bot]

Build Failed 😱

Build Id: 052f2d47-49b5-4e6c-a761-48c8ebc79ed9

• 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: 49af6f31-d26a-4863-84c4-6a1731dd294c

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

• image: gcr.io/agones-images/agones-controller:1.12.0-07aa310
• image: gcr.io/agones-images/agones-sdk:1.12.0-07aa310
• image: gcr.io/agones-images/agones-ping:1.12.0-07aa310
• Linux C++ SDK (build): agonessdk-1.12.0-07aa310-linux-arch_64.tar.gz
• SDK Server: agonessdk-server-1.12.0-07aa310.zip

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

• https://07aa310-dot-preview-dot-agones-images.appspot.com/

To install this version:

• git fetch https://github.com/googleforgames/agones.git pull/1949/head:pr_1949 && git checkout pr_1949
• helm install ./install/helm/agones --namespace agones-system --name agones --set agones.image.tag=1.12.0-07aa310

[google-oss-robot]

[APPROVALNOTIFIER] This PR is APPROVED

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

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 [markmandel,roberthbailey]

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

[google-oss-robot]

New changes are detected. LGTM label has been removed.

[agones-bot]

Build Succeeded 👏

Build Id: 58ec637a-27ae-4d0f-8dc1-8a13009fc7e2

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

• image: gcr.io/agones-images/agones-controller:1.12.0-bf8a69f
• image: gcr.io/agones-images/agones-sdk:1.12.0-bf8a69f
• image: gcr.io/agones-images/agones-ping:1.12.0-bf8a69f
• Linux C++ SDK (build): agonessdk-1.12.0-bf8a69f-linux-arch_64.tar.gz
• SDK Server: agonessdk-server-1.12.0-bf8a69f.zip

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

• https://bf8a69f-dot-preview-dot-agones-images.appspot.com/

To install this version:

• git fetch https://github.com/googleforgames/agones.git pull/1949/head:pr_1949 && git checkout pr_1949
• helm install ./install/helm/agones --namespace agones-system --name agones --set agones.image.tag=1.12.0-bf8a69f