Support Laravel 8 (#16)

Author: mikebarlow

composer.json

@@ -18,12 +18,12 @@
     }
   ],
   "require": {
-    "php": "^7.1.3",
-    "illuminate/support": "^6.0|^7.0",
+    "php": "^7.3.0",
+    "illuminate/support": "^6.0|^7.0|^8.0",
     "aws/aws-sdk-php": "^3.52"
   },
   "require-dev": {
-    "orchestra/testbench": "^5.0",
+    "orchestra/testbench": "^6.0",
     "phpunit/phpunit": "^8.0|^9.0"
   },
   "autoload": {