use phpunit/php-code-coverage ~2.2

Author: ek9

composer.json

@@ -26,7 +26,7 @@
     },
     "require": {
         "php": ">=5.3.10",
-        "phpunit/php-code-coverage": "*",
+        "phpunit/php-code-coverage": "~2.2",
         "behat/behat": "~2.4",
         "guzzle/http": "~3.0",
         "symfony/config": "~2.2,<2.4",