Add support for laravel 8.x

Author: santigarcor

composer.json

@@ -3,11 +3,11 @@
     "description": "Simple trait to manage the ownershipt of models/objects",
     "keywords": ["laravel", "ownership", "ownable", "owns"],
     "require": {
-        "illuminate/database": "^6.0|^7.0",
-        "illuminate/support": "^6.0|^7.0"
+        "illuminate/database": "^6.0|^7.0|^8.0",
+        "illuminate/support": "^6.0|^7.0|^8.0"
     },
     "require-dev": {
-        "orchestra/testbench": "^4.0|^5.0",
+        "orchestra/testbench": "^4.0|^5.0|^6.0",
         "phpunit/phpunit": "^7.5.15|^8.4|^9.0"
     },
     "autoload": {