Fixes#101734
Prior to this change, the k3s binary included a tarball containing
binaries like 'kubectl', but didn't keep a runtime reference to those
runtime dependencies in plaintext (since they were gzipped inside the
single combined k3s binary).
In order for nix's automatic runtime dependency detection to work, we
need to have a reference to them somewhere in $out.
propagatedBuildInputs seems to do the right thing for us here.
Running `nix-store -q --tree /nix/store/path/to/k3s` produces a
different output after this change which includes the `libseccomp`
reference I expect.