[travis] Fix deps=high jobs

Author: nicolas-grekas

composer.json

@@ -17,8 +17,8 @@
     ],
     "require": {
         "php": ">=5.3.3",
-        "symfony/dependency-injection" : "~2.3",
-        "symfony/config" : "~2.3,>=2.3.12",
+        "symfony/dependency-injection": "~2.3",
+        "symfony/config": "~2.3,>=2.3.12",
         "symfony/event-dispatcher": "~2.1",
         "symfony/http-foundation": "~2.3,>=2.3.19",
         "symfony/http-kernel": "~2.3,>=2.3.22",
@@ -38,7 +38,7 @@
         "symfony/finder": "~2.0,>=2.0.5",
         "symfony/intl": "~2.3",
         "symfony/security": "~2.3",
-        "symfony/form": "~2.3.0,>=2.3.5",
+        "symfony/form": "~2.3.31",
         "symfony/class-loader": "~2.1",
         "symfony/process": "~2.0,>=2.0.5",
         "symfony/validator": "~2.1",