`GitHubUserType` `mannequin` breaks decoding

[jakeatoms]

Greetings! I'm part of an org that recently migrated our org to an Enterprise Managed User org. When this happens, GitHub maps the public user accounts with the new enterprise accounts. Each user can then go and claim attribution for all their migrated history (both git and GitHub activities).

However, until this attribution takes place, users will show up in the new org as a mannequin.

This is a value that comes accross the API on User.type as mannequin. This isn't one of the enum values available in Danger and results in a decoding failure when Danger looks at reviewers and assignees on a PR.

I can gather additional information if needed, so just let me know. Thanks!

I opened this Issue for the danger/swift, too.