Fix errcheck warnings

Signed-off-by: z1cheng <imchench@gmail.com>

cmd/plugin/commands/certs/certs.go

@@ -46,7 +46,9 @@ func CreateCommand(flags *genericclioptions.ConfigFlags) *cobra.Command {
 	}
 
 	cmd.Flags().String("host", "", "Get the cert for this hostname")
-	cobra.MarkFlagRequired(cmd.Flags(), "host")
+	if err := cobra.MarkFlagRequired(cmd.Flags(), "host"); err != nil {
+		fmt.Printf("error marking flag as required: %v", err)
+	}
 	pod = util.AddPodFlag(cmd)
 	deployment = util.AddDeploymentFlag(cmd)
 	selector = util.AddSelectorFlag(cmd)

cmd/plugin/kubectl/kubectl.go

@@ -77,7 +77,11 @@ func execToWriter(args []string, writer io.Writer) error {
 		return err
 	}
 
-	go io.Copy(writer, op)
+	go func ()  {
+		if _, err := io.Copy(writer, op); err != nil {
+			fmt.Printf("Error copying output: %v\n", err)
+		}
+	}()
 	err = cmd.Run()
 	if err != nil {
 		return err