Deployment fails with recent versions of kubectl

[snicoll]

Upgrading our CI image to use a new version of kubectl leads to:

error: The gcp auth plugin has been removed.
Please use the "gke-gcloud-auth-plugin" kubectl/client-go credential plugin instead.
See https://cloud.google.com/blog/products/containers-kubernetes/kubectl-auth-changes-in-gke for further details

We need to update our CI pipeline for this new requirement. In the meantime, we'll keep the previous version of kubectl.

[mhalbritter]

We're now using Azure Spring Apps, so this is obsolete.