updated test dependencies

Author: iherwig

composer.json

@@ -34,9 +34,9 @@
         "lcobucci/jwt": "~3.2"
     },
     "require-dev": {
-        "phpunit/phpunit": "~5.6",
+        "phpunit/phpunit": "~5.7",
         "phpunit/dbunit": "~1.4",
-        "codacy/coverage": "dev-master"
+        "codacy/coverage": "~1.4"
     },
     "suggest": {
         "smarty/smarty": "Use this package to render Smarty views via SmartyView",