message: docs: Add discord to readme
diff: [![npm](https://img.shields.io/npm/l/@xmcl/core.svg)](https://github.com/voxelum/minecraft-launcher-core-node/blob/master/LICENSE)
  [![Build Status](https://github.com/voxelum/minecraft-launcher-core-node/workflows/Build/badge.svg)](https://github.com/Voxelum/minecraft-launcher-core-node/actions?query=workflow%3ABuild)
  [![Convensional Commits](https://img.shields.io/badge/Conventional%20Commits-1.0.0-yellow.svg)](https://www.conventionalcommits.org)
  +[![Discord](https://discord.com/api/guilds/405213567118213121/widget.png)](https://discord.gg/W5XVwYY7GQ)
  Provide several useful functions to build a Minecraft Launcher.
  @@ -72,6 +73,8 @@ Recommend to use the latest electron, so you don't need to setup babel with webp
  ## Getting Started
  +> Please respect the typescript interface and jsdoc in type definition if the markdown document is outdated. Contact the developer if you find the document outdated or mismatched!
  +
  Go [Getting Started](/USAGE.md) page.
  Or you can read the full [document](https://voxelum.github.io/minecraft-launcher-core-node/).
  