- composer revert phpunit to ^4 for php 5.5 support

Author: dominikmank

composer.json

@@ -24,7 +24,7 @@
         "ext-pcntl": "*"
     },
     "require-dev": {
-        "phpunit/phpunit": "^5"
+        "phpunit/phpunit": "^4"
     },
     "minimum-stability": "stable",
     "autoload": {