Add renovate and knip support

[ibgreen]

From @ilyabo based on sqlrooms experience
I followed the advice from Tom MacWright about adding Knip and Renovate:
Knip is definitely very helpful to detect unused deps/files and also finds missing deps in packages.
Renovate, I think, is useful too: aside from getting improvements, for new adopters it's easier if we don't depend on old package versions. This way it's more "compatible" when you start a new project.
So far, we've only published prereleases with the updates from Renovate.
But I'd say, bump level should depend on what kind of dependency it is. If it's just a build tool not used at runtime then it can be a patch. If it's something that can alter runtime behavior, then it's different.
We'll be holding off some crucial deps, like e.g. arrow, because duckdb still depend on v17
here's Renovate makes a nice overview: sqlrooms/sqlrooms#230