Drop laravel 5 (#26)

* tweak migration and php support

* drop laravel 5 support

Author: saqueib

composer.json

@@ -19,10 +19,10 @@
   ],
   "require": {
     "php": "^7.3|^8.0",
-    "laravel/framework": "~5.8.0|^6.0|^7.0|^8.0|^9.0"
+    "laravel/framework": "^6.0|^7.0|^8.0|^9.0"
   },
   "require-dev": {
-    "orchestra/testbench": "3.8.*|4.*|5.*|6.*",
+    "orchestra/testbench": "4.*|5.*|6.*",
     "mockery/mockery": "^0.9.4 || ~1.0",
     "phpunit/phpunit": "^8.5"
   },