Update composer.json

Author: jenssegers

composer.json

@@ -17,9 +17,10 @@
         "illuminate/events": "^5.1"
     },
     "require-dev": {
-        "orchestra/testbench": "~3.1.0",
-        "mockery/mockery": "*",
-        "satooshi/php-coveralls": "*"
+        "phpunit/phpunit": "^4.0|^5.0",
+        "orchestra/testbench": "^3.1",
+        "mockery/mockery": "^0.9",
+        "satooshi/php-coveralls": "^0.6"
     },
     "autoload": {
         "psr-0": {