fixed Composer constraints

Author: fabpot

composer.json

@@ -24,11 +24,11 @@
     },
     "require-dev": {
         "doctrine/collections": "~1.0",
-        "symfony/validator": "~2.6,>=2.6.8",
+        "symfony/validator": "^2.6.8",
         "symfony/http-foundation": "~2.2",
         "symfony/http-kernel": "~2.4",
         "symfony/security-csrf": "~2.4",
-        "symfony/translation": "~2.0,>=2.0.5"
+        "symfony/translation": "^2.0.5"
     },
     "conflict": {
         "symfony/doctrine-bridge": "<2.7",