Tell Laravel's guard about updated access token.

[DFurnes]

What's this PR do?

Laravel's guard keeps a $user instance cached so that multiple requests to Auth::user() don't hit the database each time. This means that we won't see any changes made to that user record until the following page load, however, unless we tell the user provider about it!

This pull request updates that cached user with Auth::setUser so that if we update a user's access token via the "refresh token" middleware, we'll get that new one on future calls to Auth::user().

How should this be reviewed?

I'll put up a PR to update Phoenix's dependencies after this is merged!

Checklist

• [ ] Tests added for new features/bug fixes.
• [ ] Is this a breaking change?

[weerd]

Does it actually break anything?

[weerd]

Sorry, I thought you added this to the checklist as a question for some reason.

[DFurnes]

Oooh, gotcha - this shouldn't be a breaking change since the APIs used by our apps stay the same!