added Laravel 8 support

Author: Owen-oj

composer.json

@@ -12,7 +12,7 @@
     "homepage": "https://github.com/owen-oj/laravel-getid3",
     "keywords": ["Laravel", "laravel-getid3","getID3"],
     "require": {
-        "illuminate/support": "^5.0|^6.0|^7.0",
+        "illuminate/support": "^5.0|^6.0|^7.0|^8.0",
         "james-heinrich/getid3": "^1.9"
     },
     "require-dev": {