Fix typo (#2358)

README.md

@@ -1763,7 +1763,7 @@ func main() {
 	// kill -9 is syscall.SIGKILL but can't be catch, so don't need add it
 	signal.Notify(quit, syscall.SIGINT, syscall.SIGTERM)
 	<-quit
-	log.Println("Shuting down server...")
+	log.Println("Shutting down server...")
 
 	// The context is used to inform the server it has 5 seconds to finish
 	// the request it is currently handling