koa-passport@next is broken!
Spent a lot of time with debugging and looking for a problem with **@next** version:
I used a lot of strategies(local, JWT...) with passed callback in `passport.authenticate` function and can't understand why `(error, user) => { }` parameters in the callback works so unpredictable.
For example, I've passed such arguments to the done callback in the strategy: `done(null, user);` after that passport.authenticate callback will be called with `(user, undefined).` 
So I have to pass such arguments to make it work properly: `done(null, null, user)` or `done(null, error)`. Sometimes, some of the parameters set to false. There's no such errors in main version of koa-passport!