Upgrade to up-spec alpha.4 and fix ci

[lukas-he]

I encountered Issues with the Linter as can be seen here in the step "Run linters on source". I wondered why the headers could not be found. This could be a possible issue. Therefore, I would argue to fix the CI in this issue, i.e., the linting but also to pin the Ubuntu version to 22.04.

Thereby, we can also upgrade the up-spec version to alpha.4.

[PLeVasseur]

closed by #308