This release contains a single bug fix which was a regression from how
setUserID could be used with v2 of the tracker. With v3, you could only clear the User ID with
setUserId(null) however, some existing v2 implementations clear this
setUserId(undefined). This update continues to allow
undefined as a valid value for clearing the user id.
- Fix undefined argument regression in setUserId and setOptOutCookie (close #991)