Extrange folder name '%!s(<nil>)'

I am using linux and when I run `abc import ...` it creates the `'%!s()'` folder.

Why it was named like that?

##### Checks

```
Version: 1.0.0-beta.2
Variant: !oss
Go version: go1.11.13
OS: linux
Arch: amd64
```

- [x] I have mentioned my `abc` version in the issue, if applicable.
- [x] This issue is not a duplicate.
- [x] This issue has a description.