Drop php 7.1 support

Author: Harlan Wilton

composer.json

@@ -13,7 +13,7 @@
         "email": "[email protected]"
     }],
     "require": {
-        "php": "^7.1",
+        "php": "^7.2.5",
         "illuminate/routing": "^5.5 || ^6.0 || ^7.0",
         "illuminate/support": "^5.5 || ^6.0 || ^7.0",
         "league/fractal": "^0.17"