To fix it temporary use this:
I. Add VCS Repo to your composer.json
"repositories": [ { "type": "vcs", "url": "https://github.com/nikolaynesov/roles.git" } ]

II. Change version of the package in composer.json

"bican/roles": "dev-master",

Hopefully it may help.

this package work with mongdb laravel 5.3

@romanbican when will this be merged?

i modified this request #64 in SOSkr@8e7d390 for Laravel 5.3

We decided to update and maintain a copy of bican roles and merged this pull request.
You can find it on packagist: https://packagist.org/packages/ultraware/roles