Draft: Bump the base image version to 22.04

The original idea is to keep the master branch in 20.04 and set up a separate branch for 22.04 to remain some sort of compatibility, since some of the packages in 20.04 is no longer available in 22.04, it will break someone's work if they use latest tag and assume it will be 20.04 forever. But the gitlab ci can only build successfully on protected branches. So I create this MR to address that.

Considering Ubuntu 20.04 is supported to 2030, we still have a long time before accepting this MR.