support php8 (munir131#8)

Author: ru90

composer.json

@@ -18,13 +18,13 @@
         }
     ],
     "require": {
-        "php": "^7.4",
+        "php": "^7.4|^8.0",
         "google/cloud-pubsub": "^1.1",
         "illuminate/queue": "8.*",
         "laravel/helpers": "^1.3"
     },
     "require-dev": {
-        "phpunit/phpunit": "^8.5"
+        "phpunit/phpunit": "9.5.10"
     },
     "autoload": {
         "psr-4": {