Moved dependencies to require

Author: ashtru

composer.json

@@ -17,13 +17,13 @@
         "php": ">=5.6",
         "ext-curl": "*",
         "ext-json": "*",
-        "ext-mbstring": "*"
-    },
-    "require-dev": {
-        "phpunit/phpunit": "~4.8",
+        "ext-mbstring": "*",
         "cache/apcu-adapter": "1.0.0",
         "firebase/php-jwt": "5.0.0"
     },
+    "require-dev": {
+        "phpunit/phpunit": "~4.8"
+    },
     "autoload": {
         "psr-4": { "CyberSource\\" : "lib/" }
     },