revert phpunit version to 5 to 4

Author: webwizo

composer.json

@@ -24,7 +24,7 @@
         "php": "~5.5|~7.0"
     },
     "require-dev": {
-        "phpunit/phpunit": "~5.0",
+        "phpunit/phpunit": "4.*",
         "scrutinizer/ocular": "~1.1",
         "squizlabs/php_codesniffer": "~2.3",
         "orchestra/testbench": "~3.2"