kokoro: update GKE auth plugin package name to google-cloud-cli (#277)

The legacy google-cloud-sdk-gke-gcloud-auth-plugin package has been
deprecated and removed from active Google Cloud APT repositories,
causing apt-get install to fail with:
"Package 'google-cloud-sdk-gke-gcloud-auth-plugin' has no installation
candidate" and aborting Kokoro executor provisioning with exit code 100.

Update the package name in kokoro_install_dependencies to the modern
Google Cloud CLI package: google-cloud-cli-gke-gcloud-auth-plugin.

https://docs.cloud.google.com/kubernetes-engine/docs/deprecations/auth-plugin

Author: AgraVator

.kokoro/psm_interop_kokoro_lib.sh

@@ -1364,7 +1364,7 @@ kokoro_install_dependencies() {
   sudo DEBIAN_FRONTEND=noninteractive apt-get -qq remove needrestart
   sudo DEBIAN_FRONTEND=noninteractive apt-get -qq update
   sudo DEBIAN_FRONTEND=noninteractive apt-get -qq install --auto-remove \
-    google-cloud-sdk-gke-gcloud-auth-plugin \
+    google-cloud-cli-gke-gcloud-auth-plugin \
     kubectl \
     parallel
   sudo rm -rf /var/lib/apt/lists