Update getClientDetails to return 'scope' if client implements `Tappleby\OAuth2\Models\ScopeInterface`
Update to latest version of oauth2-server-php

- Implement getClientScope
- Test for isPublicClient
- Was missing m::close on mockery which found a minor issue with `getRestrictedGrantTypes`
Ensure the rest of tests have Mocker::close.
Merge branch 'master' of github.com:tappleby/laravel-oauth2-server