chore: update readme contact (#200)

README.md

@@ -126,3 +126,8 @@ Enjoy it!
 
 [![FlowGram.AI Contributors](https://contrib.rocks/image?repo=bytedance/flowgram.ai)](https://github.com/bytedance/flowgram.ai/graphs/contributors)
 
+## 🌟 Contact us
+
+- Issues: [Issues](https://github.com/bytedance/flowgram.ai/issues)
+- Lark: Scan the QR code below with [Register Feishu](https://www.feishu.cn/en/) to join our FlowGram user group.
+<img src="./apps/docs/src/public/lark-group.png"/>