We need at least 1.2.3 for php7.2 prefer lowest build

Author: redthor

composer.json

@@ -23,6 +23,7 @@
         "phpunit/phpunit": "^5.0",
         "phpunit/phpunit-mock-objects": ">=3.0.4",
         "sebastian/version": ">=1.0.3",
+        "sebastian/comparator": ">=1.2.3",
         "friendsofphp/php-cs-fixer": "^2.0",
         "mikey179/vfsStream": "1.*"
     },