Update composer.json

composer.json

@@ -20,7 +20,7 @@
         "fzaninotto/faker": "^1.9",
         "mockery/mockery": "^1.3.1",
         "nunomaduro/collision": "^4.1",
-        "phpunit/phpunit": "^8.5|^9.0"
+        "phpunit/phpunit": "^8.5"
     },
     "config": {
         "optimize-autoloader": true,