adding dependency on symfony/validator - needed by ValidationPass

... unless this should be optional...

Author: weaverryan

composer.json

@@ -24,6 +24,7 @@
         "symfony/framework-bundle": "^2.8 || ^3.0 || ^4.0",
         "symfony/security-bundle": "^2.8 || ^3.0 || ^4.0",
         "symfony/twig-bundle": "^2.8 || ^3.0 || ^4.0",
+        "symfony/validator": "^2.8 || ^3.0 || ^4.0",
         "twig/twig": "^1.28 || ^2.0",
         "symfony/templating": "^2.8 || ^3.0 || ^4.0",
         "paragonie/random_compat": "^1 || ^2"