End twig/twig:2 support (#70)

Author: janlam7

composer.json

@@ -9,7 +9,7 @@
         "doctrine/annotations":        "^1.3",
         "phpdocumentor/type-resolver": "^1.4.0",
         "symfony/filesystem":          "^4.4||^5.0",
-        "twig/twig":                   "^2.7.2||^3.0"
+        "twig/twig":                   "^3.0"
     },
     "require-dev": {
         "composer/composer":        "^2.0.0",