Changes

feat(tikv): start use rocky8 as base image since from 8.4 (#3185)

CentOS 7 has reached the end of its life cycle. Starting from version
8.4, we began using Rocky Linux 8 as the base image.
* The default version of gcc in the new image is 8.5.0
* Temporarily use a docker image to implement the cargo cache, and after
switching the base image, try to handle the cargo cache using the PVC
 (commit: 6f8b3cb)