Bump cloudbuild image to support go 1.25

Author: nikParasyr

cloudbuild-nightly.yaml

@@ -4,7 +4,7 @@ options:
   substitution_option: ALLOW_LOOSE
   machineType: 'N1_HIGHCPU_8'
 steps:
-- name: 'gcr.io/k8s-staging-test-infra/gcb-docker-gcloud:v20250513-9264efb079'
+- name: 'gcr.io/k8s-staging-test-infra/gcb-docker-gcloud@sha256:8d6a3a5b895e6776dbe9115b75db1412fbe57299b8db329d45cb54680e462b0b' # v20251211-4c812d4cd8
   entrypoint: make
   env:
   - DOCKER_CLI_EXPERIMENTAL=enabled

cloudbuild.yaml

@@ -8,7 +8,7 @@ steps:
 # docker run --rm -it -v $(pwd):/workspace gcr.io/k8s-staging-test-infra/gcb-docker-gcloud:${TAG}
 # make clean # make sure we have something to build
 # make staging-manifests
-- name: 'gcr.io/k8s-staging-test-infra/gcb-docker-gcloud:v20250513-9264efb079'
+- name: 'gcr.io/k8s-staging-test-infra/gcb-docker-gcloud@sha256:8d6a3a5b895e6776dbe9115b75db1412fbe57299b8db329d45cb54680e462b0b' # v20251211-4c812d4cd8
   entrypoint: make
   env:
   - DOCKER_CLI_EXPERIMENTAL=enabled