Uncompatibility with Drupal 8.7.x & Latests Twig version

Problem

The latests Twig changes break the Potion internal feature.
https://twitter.com/symfony/status/1105453580755050498?s=12

You can see the issues on Travis-CI:
https://travis-ci.org/antistatique/drupal-potion

LogicException: Attribute "name" does not exist for Node "Twig\Node\CheckToStringNode".

https://github.com/twigphp/Twig/issues/2889

Resolution

Fix the problem using the latest Twig API.
Create a new alpha-02 version.
Change the number version & update the Project version with Twig version compatibility.