Adding missing dependency to a vendor_fixes

[aLekSer]

Also update vendor directory.
go mod tidy fix.

Closes #1309 .

[agones-bot]

Build Succeeded 👏

Build Id: 30ed594f-07d9-4381-b5e3-81a288d1ccad

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

• image: gcr.io/agones-images/agones-controller:1.4.0-e0e1daf
• image: gcr.io/agones-images/agones-sdk:1.4.0-e0e1daf
• image: gcr.io/agones-images/agones-ping:1.4.0-e0e1daf
• Linux C++ SDK (build): agonessdk-1.4.0-e0e1daf-linux-arch_64.tar.gz
• SDK Server: agonessdk-server-1.4.0-e0e1daf.zip

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

• https://e0e1daf-dot-preview-dot-agones-images.appspot.com/

To install this version:

• git fetch https://github.com/GoogleCloudPlatform/agones.git pull/1321/head:pr_1321 && git checkout pr_1321
• helm install ./install/helm/agones --namespace agones-system --name agones --set agones.image.tag=1.4.0-e0e1daf

[google-oss-robot]

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

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