flags: Fix --version output (#3772)

cmd/main.go

@@ -107,6 +107,7 @@ func registerApp() *cli.App {
 	app := cli.NewApp()
 	app.Name = "Minio"
 	app.Author = "Minio.io"
+	app.Version = Version
 	app.Usage = "Cloud Storage Server."
 	app.Description = `Minio is an Amazon S3 compatible object storage server. Use it to store photos, videos, VMs, containers, log files, or any blob of data as objects.`
 	app.Flags = globalFlags