Merge pull request vyuldashev#274 from vyuldashev/dependabot/composer/phpunit/phpunit-tw-8.4

Update phpunit/phpunit requirement from ^7.0 to ^8.4

Author: vyuldashev

composer.json

@@ -18,7 +18,7 @@
     "queue-interop/amqp-interop": "0.8.*"
   },
   "require-dev": {
-    "phpunit/phpunit": "^7.0",
+    "phpunit/phpunit": "^8.4",
     "illuminate/events": "^6.0",
     "mockery/mockery": "^1.0",
     "laravel/horizon": "^3.0"