Update composer.json (#7)

Author: neoteknic

composer.json

@@ -16,12 +16,12 @@
         }
     ],
     "require": {
-        "php" : "^7.0",
-        "illuminate/support": "~5.5.0|~5.6.0|~5.7.0|~5.8.0|^6.0|^7.0",
+        "php" : "^7.0|^8.0",
+        "illuminate/support": "~5.5.0|~5.6.0|~5.7.0|~5.8.0|^6.0|^7.0|^8.0",
         "graham-campbell/guzzle-factory": "^3.0"
     },
     "require-dev": {
-        "phpunit/phpunit": "^6.2|^7.0|^8.0",
+        "phpunit/phpunit": "^6.2|^7.0|^8.0|^9.0",
         "orchestra/testbench": "~3.5.0|~3.6.0",
         "mockery/mockery": "^1.1",
         "friendsofphp/php-cs-fixer": "^2.12"