Update composer.json

Author: patrickbrouwers

composer.json

@@ -31,7 +31,7 @@
     "beberlei/DoctrineExtensions": "Query/Type Doctrine2 extensions (^1.0)"
   },
   "require-dev": {
-    "phpunit/phpunit": "~4.0",
+    "phpunit/phpunit": "^7.0",
     "mockery/mockery": "~0.9",
     "gedmo/doctrine-extensions": "^2.4",
     "beberlei/DoctrineExtensions": "^1.0"