Moved test utilities to require-dev where it should have been all along

Author: WyriHaximus

composer.json

@@ -13,7 +13,6 @@
     "php": "^7.0",
     "api-clients/events": "dev-master",
     "api-clients/hydrator": "dev-master",
-    "api-clients/test-utilities": "dev-master",
     "api-clients/transport": "dev-master",
     "league/container": "^2.2",
     "league/event": "^2.1",
@@ -22,6 +21,7 @@
     "wyrihaximus/tactician-command-handler-mapper": "^1.0"
   },
   "require-dev": {
+    "api-clients/test-utilities": "dev-master",
     "humbug/humbug": "1.0.0-alpha2",
     "phake/phake": "^2.3",
     "phpspec/prophecy": "^1.6",