Add https://github.com/piercing-index/cloud-vulnerabilities scores

[pombredanne]

https://github.com/piercing-index/cloud-vulnerabilities has scoring for cloud vulnerabilities.

[pombredanne]

Actually the data is not open source but under a proprietary license (CC-BY-NC-SA) so we cannot use it.

@labyrinthinesecurity Would you be considering changing your license to a CC-BY-SA instead which would make it reusable? Thanks!