removed platform config from composer

issue #78

bootstrap.php

@@ -0,0 +1,5 @@
+<?php
+
+if (!defined('PHPUNIT_COMPOSER_INSTALL')) {
+    define('PHPUNIT_COMPOSER_INSTALL', __DIR__ . '/vendor/autoload.php');
+}

composer.json

@@ -55,10 +55,5 @@
     "scripts": {
         "php:fix": "php .php-cs-fixer.php --force",
         "php:fix:debug": "php .php-cs-fixer.php"
-    },
-    "config": {
-        "platform": {
-            "php": "7.1.3"
-        }
     }
 }

phpunit.xml

@@ -3,7 +3,7 @@
 <phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
          xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/7.5/phpunit.xsd"
          colors="true"
-         bootstrap="vendor/autoload.php">
+         bootstrap="bootstrap.php">
     <php>
         <ini name="error_reporting" value="-1"/>
     </php>