Update php minimum requirement to 7.2

Author: vigneshgurusamy

.travis.yml

@@ -3,7 +3,6 @@ language: php
 sudo: false
 
 php:
-    - 7.1
     - 7.2
     - 7.3
 

README.md

@@ -12,7 +12,7 @@
 To install this package you will need:
 
  - Laravel >= 5.6
- - PHP 7.1.3+
+ - PHP 7.2+
 
 
 Run this command to install via composer

composer.json

@@ -20,7 +20,7 @@
         }
     ],
     "require": {
-        "php": ">=7.1.3",
+        "php": ">=7.2",
         "illuminate/support": "5.6.*|5.7.*",
         "guzzlehttp/guzzle": "~6.0"
     },