Use LoadFromFile method instead Load for k8s client object

To use Load method, first the file needs to be read and passed the content
to Load method. LoadFromFile helper do it for us so no need to open the file ourself.

pkg/crc/machine/kubeconfig.go

@@ -6,7 +6,6 @@ import (
 	"crypto/x509"
 	goerrors "errors"
 	"fmt"
-	"io/ioutil"
 	"net"
 	"net/http"
 	"net/url"
@@ -95,11 +94,7 @@ func WriteKubeconfig(ip string, clusterConfig *ClusterConfig) error {
 }
 
 func certificateAuthority(kubeconfigFile string) ([]byte, error) {
-	bin, err := ioutil.ReadFile(kubeconfigFile)
-	if err != nil {
-		return nil, err
-	}
-	builtin, err := clientcmd.Load(bin)
+	builtin, err := clientcmd.LoadFromFile(kubeconfigFile)
 	if err != nil {
 		return nil, err
 	}