ubuntu22: bump cmake to 3.28.3 and root to 6.30.04

The main interest of this one is not the Root bump, but the CMake one. Starting with CMake 3.28 the FetchContent_Declare got a new option (EXCLUDE_FROM_ALL) which makes the dependent projects build (potentially) much less stuff than before (i.e. really just what they use).

Especially interesting for projects using e.g. Jpp (example(s) of such project(s) will hopefully be provided at the Caen workshop).