[suggestion]update the bRPC users on website

[Shuai Liu]

Hi, all

I suggest adding the following bRPC users on website:
* 维沃（vivo）
* 第四范式（4paradigm）
* 小红书
* 作业帮

Ref: https://github.com/apache/incubator-brpc/blob/master/community/cases.md

Best Regards,
serverglen