First test for the agones unity client sdk

[aallbrig]

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
/kind release

What this PR does / Why we need it:
Following instructions proposed in #3886 I set up a local environment to contribute to agones unity client sdk.

I noticed there wasn't a test. This adds a first test. I don't think it's a good test so please offer up what might make for a better first test.

Which issue(s) this PR fixes:

Closes #

Special notes for your reviewer:

[agones-bot]

Build Succeeded 👏

Build Id: 5078706a-0651-4905-aa15-cae53be14e47

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:1.42.0-dev-5c54ed5-amd64
• image: us-docker.pkg.dev/agones-images/ci/agones-extensions:1.42.0-dev-5c54ed5-amd64
• image: us-docker.pkg.dev/agones-images/ci/agones-sdk:1.42.0-dev-5c54ed5-linux-amd64
• image: us-docker.pkg.dev/agones-images/ci/agones-ping:1.42.0-dev-5c54ed5-amd64
• image: us-docker.pkg.dev/agones-images/ci/agones-allocator:1.42.0-dev-5c54ed5-amd64
• Linux C++ SDK (build): agonessdk-1.42.0-dev-5c54ed5-amd64-linux-arch_64.tar.gz
• SDK Server: agonessdk-server-1.42.0-dev-5c54ed5-amd64.zip

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

• https://5c54ed5-dot-preview-dot-agones-images.appspot.com/

To install this version:

• git fetch https://github.com/googleforgames/agones.git pull/3887/head:pr_3887 && git checkout pr_3887
• helm install agones ./install/helm/agones --namespace agones-system --set agones.image.registry=us-docker.pkg.dev/agones-images/ci --set agones.image.tag=1.42.0-dev-5c54ed5-amd64