Upgrade web-push-php

Author: Minishlink

README.md

@@ -9,12 +9,14 @@ Navigating through the commits and files will help you build:
 
 ## Requirements
 - Chrome or Firefox
-- PHP 5.6+
+- PHP 7.1+
     - gmp
     - mbstring
     - curl
     - openssl
 
+PHP 5.6+ is no longer maintained, but you can checkout the `v1.x` branch.
+
 ## Installation
 ```bash
 $ composer create-project minishlink/web-push-php-example

composer.json

@@ -10,6 +10,6 @@
         }
     ],
     "require": {
-        "minishlink/web-push": "^1.4"
+        "minishlink/web-push": "^3.0"
     }
 }