[CVE]A heap overflow in the lua-cjson library

[NagamineLee]

CVE has revealed a a critical vulnerability about Redis，but details of the vulnerability are more related to cjson.
By reviewing the Redis source code, the cjson library used in Redis is also derived from the Lua CJSON official.
So, the problem may also happen in OpenResty.

A heap overflow in the lua-cjson library
Severity: high
CVE-2022-24834

[zhuizhuhaomeng]

Ported the code from redis: #94