Removing Interpolation-only expressions

[chrisst]

Terraform 0.12.14 will start adding deprecation warnings for any strings that
only contain an interpolation as they can be replaced with straight references.

More at https://discuss.hashicorp.com/t/terraform-0-12-14-released/

This syntax has been available since Terraform 0.12 launched and it looks like 0.12 is the preferred version. Just in case I added a version constraint for

[chrisst]

/assign @pooneh-m

[agones-bot]

Build Succeeded 👏

Build Id: 68c079ea-a008-4926-a84b-afcb957398b0

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

• image: gcr.io/agones-images/agones-controller:1.4.0-6b178da
• image: gcr.io/agones-images/agones-sdk:1.4.0-6b178da
• image: gcr.io/agones-images/agones-ping:1.4.0-6b178da
• Linux C++ SDK (build): agonessdk-1.4.0-6b178da-linux-arch_64.tar.gz
• SDK Server: agonessdk-server-1.4.0-6b178da.zip

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

• https://6b178da-dot-preview-dot-agones-images.appspot.com/

To install this version:

• git fetch https://github.com/GoogleCloudPlatform/agones.git pull/1317/head:pr_1317 && git checkout pr_1317
• helm install ./install/helm/agones --namespace agones-system --name agones --set agones.image.tag=1.4.0-6b178da

[pooneh-m]

Thanks for the change. It is good to have a professional terraformer on the project. :)

[google-oss-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: chrisst, pooneh-m

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• OWNERS [pooneh-m]

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[google-oss-robot]

New changes are detected. LGTM label has been removed.

[agones-bot]

Build Succeeded 👏

Build Id: 6594c427-ecf8-422c-8204-8350b77d0eaa

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

• image: gcr.io/agones-images/agones-controller:1.4.0-2924517
• image: gcr.io/agones-images/agones-sdk:1.4.0-2924517
• image: gcr.io/agones-images/agones-ping:1.4.0-2924517
• Linux C++ SDK (build): agonessdk-1.4.0-2924517-linux-arch_64.tar.gz
• SDK Server: agonessdk-server-1.4.0-2924517.zip

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

• https://2924517-dot-preview-dot-agones-images.appspot.com/

To install this version:

• git fetch https://github.com/GoogleCloudPlatform/agones.git pull/1317/head:pr_1317 && git checkout pr_1317
• helm install ./install/helm/agones --namespace agones-system --name agones --set agones.image.tag=1.4.0-2924517