Added Laravel 7 support

Author: ssx

composer.json

@@ -4,12 +4,12 @@
     "type": "library",
     "keywords": [ "laravel", "validation", "ip" ],
     "require": {
-        "illuminate/contracts": "^5.5|^6.0",
+        "illuminate/contracts": "^5.5|^6.0|^7.0",
         "symfony/http-foundation": "^3.3"
     },
     "require-dev": {
-        "orchestra/testbench": "^3.5",
-        "phpunit/phpunit": "^6.3"
+        "orchestra/testbench": "^3.5|^5.0",
+        "phpunit/phpunit": "^6.3|^9.0"
     },
     "license": "Apache-2.0",
     "authors": [