treewide: replace deprecated grpc.Dial with grpc.NewClient

Change-Id: I925912ca1ee01d547fd9c1813eb083a2cd9a590a
Reviewed-on: https://review.monogon.dev/c/monogon/+/3858
Reviewed-by: Jan Schär <jan@monogon.tech>
Tested-by: Jenkins CI
diff --git a/metropolis/cli/metroctl/cmd_node_approve.go b/metropolis/cli/metroctl/cmd_node_approve.go
index 65d2811..c966d6e 100644
--- a/metropolis/cli/metroctl/cmd_node_approve.go
+++ b/metropolis/cli/metroctl/cmd_node_approve.go
@@ -22,9 +22,9 @@
 	Args:  PrintUsageOnWrongArgs(cobra.MaximumNArgs(1)), // One positional argument: node ID
 	RunE: func(cmd *cobra.Command, args []string) error {
 		ctx, _ := signal.NotifyContext(context.Background(), os.Interrupt)
-		cc, err := dialAuthenticated(ctx)
+		cc, err := newAuthenticatedClient(ctx)
 		if err != nil {
-			return fmt.Errorf("while dialing node: %w", err)
+			return fmt.Errorf("while creating client: %w", err)
 		}
 		mgmt := api.NewManagementClient(cc)