Make k8s v1.12.3 the default

Makefile

@@ -23,7 +23,7 @@ BUILDROOT_BRANCH ?= 2018.05
 REGISTRY?=gcr.io/k8s-minikube
 
 HYPERKIT_BUILD_IMAGE 	?= karalabe/xgo-1.10.x
-BUILD_IMAGE 	?= k8s.gcr.io/kube-cross:v1.10.1-1
+BUILD_IMAGE 	?= k8s.gcr.io/kube-cross:v1.12.3-1
 ISO_BUILD_IMAGE ?= $(REGISTRY)/buildroot-image
 
 ISO_VERSION ?= v0.30.0

pkg/minikube/constants/constants.go

@@ -22,13 +22,13 @@ import (
 	"path/filepath"
 	"runtime"
 	"strings"
+	"time"
 
 	"github.com/blang/semver"
 	"github.com/golang/glog"
 	"k8s.io/client-go/tools/clientcmd"
 	"k8s.io/client-go/util/homedir"
 	minikubeVersion "k8s.io/minikube/pkg/version"
-	"time"
 )
 
 // APIServerPort is the port that the API server should listen on.
@@ -125,7 +125,7 @@ const (
 var DefaultIsoUrl = fmt.Sprintf("https://storage.googleapis.com/%s/minikube-%s.iso", minikubeVersion.GetIsoPath(), minikubeVersion.GetIsoVersion())
 var DefaultIsoShaUrl = DefaultIsoUrl + ShaSuffix
 
-var DefaultKubernetesVersion = "v1.10.0"
+var DefaultKubernetesVersion = "v1.12.3"
 
 var ConfigFilePath = MakeMiniPath("config")
 var ConfigFile = MakeMiniPath("config", "config.json")