Add licence to cancelot.sh

[markmandel]

What type of PR is this?

Uncomment only one /kind <> line, press 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:

Also includes a bash bang line at the top too.

Which issue(s) this PR fixes:

N/A

Special notes for your reviewer:

[gongmax]

Thanks for catching this!

[google-oss-prow]

[APPROVALNOTIFIER] This PR is APPROVED

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

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]

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

[agones-bot]

Build Failed 😱

Build Id: 97e01756-9c7e-4c64-987d-ed5aeb00ae55

• Cloud Build view
• Cloud Build log download

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

[gongmax]

CI timed out waiting for becoming a leader. Retrying.

[agones-bot]

Build Succeeded 👏

Build Id: f4e8901d-d87f-4890-b111-588d21066c4c

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-ff20e15-amd64
• image: us-docker.pkg.dev/agones-images/ci/agones-sdk:1.31.0-ff20e15-linux-amd64
• image: us-docker.pkg.dev/agones-images/ci/agones-ping:1.31.0-ff20e15-amd64
• image: us-docker.pkg.dev/agones-images/ci/agones-allocator:1.31.0-ff20e15-amd64
• Linux C++ SDK (build): agonessdk-1.31.0-ff20e15-amd64-linux-arch_64.tar.gz
• SDK Server: agonessdk-server-1.31.0-ff20e15-amd64.zip

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

• https://ff20e15-dot-preview-dot-agones-images.appspot.com/

To install this version:

• git fetch https://github.com/googleforgames/agones.git pull/3055/head:pr_3055 && git checkout pr_3055
• 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-ff20e15-amd64