Add support for Laravel 8

Author: Adrian Sacchi

composer.json

@@ -21,13 +21,13 @@
     ],
     "require": {
         "php": "^7.2",
-        "illuminate/contracts": "~70",
-        "illuminate/support": "~7.0",
-        "illuminate/database": "~7.0"
+        "illuminate/contracts": "~8.0",
+        "illuminate/support": "~8.0",
+        "illuminate/database": "~8.0"
     },
     "require-dev": {
         "orchestra/testbench": "^4.0",
-        "phpunit/phpunit": "~7.0|^8.0"
+        "phpunit/phpunit": "^7.0|^8.0|^9.0"
     },
     "autoload": {
         "psr-4": {