docs: update DingTalk group link format in README (#4300)

- Adjust DingTalk group reference to use consistent formatting
- Ensure clarity for community contact information

Signed-off-by: mingcheng <mingcheng@apache.org>

Author: mingcheng

README.md

@@ -77,7 +77,7 @@ Join the conversation and help the community. We have a number of ways for you t
 - **Developer Group**: <dragonfly-developers@googlegroups.com>
 - **Maintainer Group**: <dragonfly-maintainers@googlegroups.com>
 - **Twitter**: [@dragonfly_oss](https://twitter.com/dragonfly_oss)
-- **DingTalk**: [22880028764](https://qr.dingtalk.com/action/joingroup?code=v1,k1,pkV9IbsSyDusFQdByPSK3HfCG61ZCLeb8b/lpQ3uUqI=&_dt_no_comment=1&origin=11)
+- **DingTalk Group**: `22880028764`
 
 and you can also seek the main community information in the [community repository](https://github.com/dragonflyoss/community).
 In this repository, you can find the [community meeting minutes, community meeting notes, and more](https://github.com/dragonflyoss/community/tree/master/meetings).