Allow phpunit 4.2

Author: timgws

composer.json

@@ -24,7 +24,7 @@
     "elasticsearch/elasticsearch": ">1.0 <2.2"
   },
   "require-dev": {
-    "phpunit/phpunit": "~5.0",
+    "phpunit/phpunit": "~4.2|~5.0",
     "mockery/mockery": "^0.9.4"
   },
   "autoload": {