Merge pull request #2420 from k8s-infra-cherrypick-robot/cherry-pick-2419-to-release-0.12

[release-0.12] 🌱 data: use latest Flatcar stable from image-builder

Author: k8s-ci-robot

test/e2e/data/e2e_conf.yaml

@@ -188,7 +188,7 @@ variables:
   SSH_USER_MACHINE: "ubuntu"
   EXP_KUBEADM_BOOTSTRAP_FORMAT_IGNITION: "true"
   # The Flatcar image produced by the image-builder
-  OPENSTACK_FLATCAR_IMAGE_NAME: "flatcar-stable-4081.2.0-kube-v1.31.2"
+  OPENSTACK_FLATCAR_IMAGE_NAME: "flatcar-stable-4152.2.0-kube-v1.31.2"
   # A plain Flatcar from the Flatcar releases server
   FLATCAR_IMAGE_NAME: "flatcar_production_openstack_image"