Update composer.json to use phpunit v9.5

Author: rkesarwa

README.md

@@ -13,7 +13,7 @@ If you want to install SDK from Packagist,add the following dependency to your a
 ```
 ## Prerequisites
 
-- PHP 5.3 or above
+- PHP 7.3 or above
    - [curl](http://php.net/manual/en/book.curl.php), [openssl](http://php.net/manual/en/book.openssl.php), [soap](http://php.net/manual/en/book.soap.php) extensions must be enabled
 - A CyberSource account. You can create an evaluation account [here](http://www.cybersource.com/register/).
 - A CyberSource transaction key. You will need to set your merchant ID and transaction key in the ````cybs.ini```` file in ````lib/conf````. Instructions on obtaining a transaction key can be found [here](http://www.cybersource.com/developers/integration_methods/simple_order_and_soap_toolkit_api/soap_api/html/wwhelp/wwhimpl/js/html/wwhelp.htm#href=Intro.04.3.html).
@@ -30,6 +30,12 @@ You'll first need to make sure you have Composer installed. You can follow the i
 Linux: composer.phar install 
 Windows: composer install 
 ```
+If you already have composer installed for the project, you'll need to run the update command as below
+```
+Linux: composer.phar update 
+Windows: composer update
+```
+
 Then, to use the client, you'll need to include the Composer-generated autoload file:
 
 ```php

composer.json

@@ -15,13 +15,13 @@
     }
   ],
   "require": {
-    "php": ">=5.3",
+    "php": ">=7.3",
     "ext-curl": "*",
     "ext-openssl": "*",
     "ext-soap": "*"
   },
   "require-dev": {
-      "phpunit/phpunit": "3.7.*"
+      "phpunit/phpunit": "9.5.*"
   },
   "autoload": {
     "classmap": ["lib/"]

test/CybsSoapClientTest.php

@@ -1,6 +1,8 @@
 <?php
+require __DIR__ . '/../vendor/autoload.php';
+use PHPUnit\Framework\TestCase;
 
-class CybsSoapClientTestCase extends PHPUnit_Framework_TestCase
+class CybsSoapClientTestCase extends TestCase
 {
     public function testClient()
     {