Update _index.md

[deibu]

Added missing word.

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:

Which issue(s) this PR fixes:

Closes #

Special notes for your reviewer:

[google-cla]

Thanks for your pull request! It looks like this may be your first contribution to a Google open source project. Before we can look at your pull request, you'll need to sign a Contributor License Agreement (CLA).

View this failed invocation of the CLA check for more information.

For the most up to date status, view the checks section at the bottom of the pull request.

[agones-bot]

Build Succeeded 👏

Build Id: 3afe3c7a-3825-4910-bfd3-d543d078196c

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:1.31.0-22fc7eb-amd64
• image: us-docker.pkg.dev/agones-images/ci/agones-sdk:1.31.0-22fc7eb-linux-amd64
• image: us-docker.pkg.dev/agones-images/ci/agones-ping:1.31.0-22fc7eb-amd64
• image: us-docker.pkg.dev/agones-images/ci/agones-allocator:1.31.0-22fc7eb-amd64
• Linux C++ SDK (build): agonessdk-1.31.0-22fc7eb-amd64-linux-arch_64.tar.gz
• SDK Server: agonessdk-server-1.31.0-22fc7eb-amd64.zip

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

• https://22fc7eb-dot-preview-dot-agones-images.appspot.com/

To install this version:

• git fetch https://github.com/googleforgames/agones.git pull/3045/head:pr_3045 && git checkout pr_3045
• helm install agones ./install/helm/agones --namespace agones-system --agones.image.release=us-docker.pkg.dev/agones-images/ci --set agones.image.tag=1.31.0-22fc7eb-amd64

[google-oss-prow]

[APPROVALNOTIFIER] This PR is APPROVED

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

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Needs approval from an approver in each of these files:

• OWNERS [roberthbailey]

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