Add a security policy that uses g.co/vulnz for intake

[roberthbailey]

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: Adds a security policy for agones.

Which issue(s) this PR fixes:

Closes #

Special notes for your reviewer:

[agones-bot]

Build Succeeded 👏

Build Id: e788fd77-dc61-48b7-a57c-f3cef3cce598

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

• image: gcr.io/agones-images/agones-controller:1.14.0-e81c9d2
• image: gcr.io/agones-images/agones-ping:1.14.0-e81c9d2
• Linux C++ SDK (build): agonessdk-1.14.0-e81c9d2-linux-arch_64.tar.gz
• SDK Server: agonessdk-server-1.14.0-e81c9d2.zip

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

• https://e81c9d2-dot-preview-dot-agones-images.appspot.com/

To install this version:

• git fetch https://github.com/googleforgames/agones.git pull/2044/head:pr_2044 && git checkout pr_2044
• helm install ./install/helm/agones --namespace agones-system --name agones --set agones.image.tag=1.14.0-e81c9d2

[agones-bot]

Build Succeeded 👏

Build Id: f089b90e-3ca0-4d45-abc4-72fdaba70e38

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

• image: gcr.io/agones-images/agones-controller:1.14.0-da2b8a1
• image: gcr.io/agones-images/agones-ping:1.14.0-da2b8a1
• Linux C++ SDK (build): agonessdk-1.14.0-da2b8a1-linux-arch_64.tar.gz
• SDK Server: agonessdk-server-1.14.0-da2b8a1.zip

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

• https://da2b8a1-dot-preview-dot-agones-images.appspot.com/

To install this version:

• git fetch https://github.com/googleforgames/agones.git pull/2044/head:pr_2044 && git checkout pr_2044
• helm install ./install/helm/agones --namespace agones-system --name agones --set agones.image.tag=1.14.0-da2b8a1

[markmandel]

nice!

[google-oss-robot]

[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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