Vendoring fails in 0.11.84

Hi Alex,

I tried updating the openSUSE package for arkade, but the vendoring fails:

```bash
go: downloading github.com/vbatts/tar-split v0.12.2
go: github.com/alexellis/arkade/cmd/fstail imports
github.com/alexellis/fstail/pkg/fstail: github.com/alexellis/fstail@v0.0.0-20250917111842-2ab578ec2afb: replacement directory ../fstail does not exist
go: github.com/alexellis/arkade/cmd/gha imports
github.com/alexellis/gha-bump/pkg/ghabump: github.com/alexellis/gha-bump@v0.0.0: replacement directory ../gha-bump does not exist
```

Which is not surprising, as there are no `../fstail` or `../ghabump` directories when cloning only the `arkade` repository.

Unfortunately I cannot patch the `go.mod` easily before vendoring due to the build tooling. Any ideas?

Kind Regards,
Johannes