fix CONFORMANCE_CI_ARTIFACTS_KUBERNETES_VERSION, missing v suffix

Author: damdo

test/e2e/data/e2e_eks_conf.yaml

@@ -130,7 +130,7 @@ variables:
   EXP_EKS_ADD_ROLES: "false"
   VPC_ADDON_VERSION: "v1.18.3-eksbuild.2"
   KUBE_PROXY_ADDON_VERSION: "v1.31.0-eksbuild.5"
-  CONFORMANCE_CI_ARTIFACTS_KUBERNETES_VERSION: "1.31.0"
+  CONFORMANCE_CI_ARTIFACTS_KUBERNETES_VERSION: "v1.31.0"
   IP_FAMILY: "IPv4"
   CAPA_LOGLEVEL: "4"
   EXP_EXTERNAL_RESOURCE_GC: "true"