Temporarily Run Builds Serially

This commit modifies the cloudbuild template to	run the	k8s buils serially.

This is	just temporary to finish the nov '24 builds while we investigate a
memory spike.

Signed-off-by: Adolfo García Veytia (Puerco) <[email protected]>

Author: puerco

gcb/stage/cloudbuild.yaml

@@ -78,6 +78,7 @@ steps:
   - "K8S_REPO=${_K8S_REPO}"
   - "K8S_REF=${_K8S_REF}"
   - GOOGLE_SERVICE_ACCOUNT_NAME=krel-staging@k8s-releng-prod.iam.gserviceaccount.com
+  - "KUBE_PARALLEL_BUILD_MEMORY=64"
   secretEnv:
   - GITHUB_TOKEN
   - DOCKERHUB_TOKEN