Detect Twig depreciations

[prudloff-insite]

It would be useful if twigcs could detect deprecated features: https://twig.symfony.com/doc/1.x/recipes.html#displaying-deprecation-notices

Steps required to reproduce the problem

1. Write a Twig 2 template containing this:

{% spaceless %}
  <div>
  </div>
{% endspaceless %}

2. Run ./vendor/bin/twigcs -t 2 on it.

Expected Result

twigcs warns that the spaceless tag is deprecated and removed in Twig 3.

Actual Result

No warning is displayed.