It currently fails with this:
```
error: lib.fileset.toSource: `root`
(/tmp/nix-shell-19054-0/tmp.MB62qzBqsj/base) is a string-like value, but
it should be a path instead.
Paths in strings are not supported by `lib.fileset`, use
`lib.sources` or derivations instead.
```
Resolves#416175
We have added nixpkgs-vet as a regular package to nixpkgs a while ago,
so we can now use it from pinned nixpkgs. This avoids pulling a
platform-specific binary version from upstream.
This change also allows to run the tool easily locally, the same way as
other tools:
nix-build ci -A nixpkgs-vet
This will do a full check of the repo with the exception of
nixpkgs-vet's "ratchet" checks: Those depend on having two branches to
compare, but the default is to only look at the head branch. Those
ratchet checks will still be run in CI, though.
Everything gets moved into the `ci/` top-level directory.
We keep behind `maintainers/scripts/check-by-name.sh` and `pkgs/test/check-by-name/pinned-version.txt` as they are going to cause CI errors and confusion until we get all the way through the various channels.
They'll be removed in about a week or so.
