Updating CI pipeline(s)

[kjvbrt]

No description provided.

[jmcarcell]

I can include FCCAnalyses to have the same CI as the rest of the Key4hep and HEP-FCC packages. I don't remember why this wasn't done. The three things that I update in all the repositories are:

• The CI workflows to build and test using the Key4hep (now also the LCG) stacks
• A common .clang-format
• Common Github rules (for example, making sure that the build and test workflows are required for making the merge button green or that squash is preferred)
  If you want, we can opt in for any of these for FCCAnalyses

[kjvbrt]

Hi @jmcarcell, let's go for it :)
I'm not sure whether the "Common Github rules" will fit the FCCAnalyses, but let's set up those as well and then we will see.
I presume that we can have CI workflows on top of the ones provided by Key4hep CI settings?

I want to merge one more pull request beforehand (PR #500)