Fixed invalid JSON in composer file

Author: James Wigger

composer.json

@@ -19,7 +19,7 @@
    },
    "require-dev": {
       "phpunit/phpunit": "~5.0",
-      "orchestra/testbench": "~3.3",
+      "orchestra/testbench": "~3.3"
    },
    "autoload":{  
       "psr-4":{