update testbench

Author: Kevin Buchholz

composer.json

@@ -30,7 +30,7 @@
     },
     "require-dev": {
         "consistence/coding-standard": "3.7",
-        "orchestra/testbench": "~3.0",
+        "orchestra/testbench": "~3.0 || 4.*",
         "phpmd/phpmd": "^2.6",
         "phpunit/phpunit": "7.4.* || 8.3.*",
         "slevomat/coding-standard": "4.8.7",