Bring Rust SDK dependencies up to date

[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
/kind release

What this PR does / Why we need it:

These were quite old, and running on an even older Rust edition.

This brings everything up to date.

Which issue(s) this PR fixes:

N/A

Special notes for your reviewer:

N/A

[google-oss-prow]

[APPROVALNOTIFIER] This PR is APPROVED

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

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 Succeeded 👏

Build Id: 0db77c1d-8050-4b1b-a8e7-e3f0455d38e4

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:1.34.0-dev-96aca45-amd64
• image: us-docker.pkg.dev/agones-images/ci/agones-extensions:1.34.0-dev-96aca45-amd64
• image: us-docker.pkg.dev/agones-images/ci/agones-sdk:1.34.0-dev-96aca45-linux-amd64
• image: us-docker.pkg.dev/agones-images/ci/agones-ping:1.34.0-dev-96aca45-amd64
• image: us-docker.pkg.dev/agones-images/ci/agones-allocator:1.34.0-dev-96aca45-amd64
• Linux C++ SDK (build): agonessdk-1.34.0-dev-96aca45-amd64-linux-arch_64.tar.gz
• SDK Server: agonessdk-server-1.34.0-dev-96aca45-amd64.zip

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

• https://96aca45-dot-preview-dot-agones-images.appspot.com/

To install this version:

• git fetch https://github.com/googleforgames/agones.git pull/3305/head:pr_3305 && git checkout pr_3305
• helm install agones ./install/helm/agones --namespace agones-system --set agones.image.registry=us-docker.pkg.dev/agones-images/ci --set agones.image.tag=1.34.0-dev-96aca45-amd64