PLATFORM-703: updated version of phpunit

Author: n1te1337

composer.json

@@ -10,7 +10,7 @@
     "chrisboulton/php-resque": "dev-master"
   },
   "require-dev": {
-    "phpunit/phpunit": "4.5.*",
+    "phpunit/phpunit": "^4.8",
     "squizlabs/php_codesniffer": "2.3.0",
     "predis/predis": "^1.0"
   },