Allow version 2.0 of sebastian/environment

Author: sebastianbergmann

composer.json

@@ -26,7 +26,7 @@
         "phpunit/php-token-stream": "^1.4.2",
         "phpunit/php-text-template": "~1.2",
         "sebastian/code-unit-reverse-lookup": "~1.0",
-        "sebastian/environment": "^1.3.2",
+        "sebastian/environment": "^1.3.2 || ^2.0",
         "sebastian/version": "~1.0|~2.0"
     },
     "require-dev": {