chore: update phpunit/phpunit 8.5.52

Author: ewaostrowska

modules/swagger-codegen/src/main/resources/php/README.mustache

@@ -59,6 +59,8 @@ composer install
 ./vendor/bin/phpunit
 ```
 
+**Note:** Running tests requires PHP 7.2 or later, while the runtime library supports PHP 5.5 and later.
+
 ## Getting Started
 
 Please follow the [installation procedure](#installation--usage) and then run the following:

modules/swagger-codegen/src/main/resources/php/api_test.mustache

@@ -30,34 +30,34 @@ use \{{invokerPackage}}\ObjectSerializer;
  * @author   Swagger Codegen team
  * @link     https://github.com/swagger-api/swagger-codegen
  */
-{{#operations}}class {{classname}}Test extends \PHPUnit_Framework_TestCase
+{{#operations}}class {{classname}}Test extends \PHPUnit\Framework\TestCase
 {
 
     /**
      * Setup before running any test cases
      */
-    public static function setUpBeforeClass()
+    public static function setUpBeforeClass(): void
     {
     }
 
     /**
      * Setup before running each test case
      */
-    public function setUp()
+    public function setUp(): void
     {
     }
 
     /**
      * Clean up after running each test case
      */
-    public function tearDown()
+    public function tearDown(): void
     {
     }
 
     /**
      * Clean up after running all test cases
      */
-    public static function tearDownAfterClass()
+    public static function tearDownAfterClass(): void
     {
     }
     {{#operation}}

modules/swagger-codegen/src/main/resources/php/composer.mustache

@@ -26,7 +26,7 @@
         "guzzlehttp/guzzle": "^6.2"
     },
     "require-dev": {
-        "phpunit/phpunit": "^4.8",
+        "phpunit/phpunit": "^8.5.52",
         "squizlabs/php_codesniffer": "~2.6",
         "friendsofphp/php-cs-fixer": "~2.12"
     },

modules/swagger-codegen/src/main/resources/php/model_test.mustache

@@ -30,34 +30,34 @@ namespace {{invokerPackage}};
  * @author      Swagger Codegen team
  * @link        https://github.com/swagger-api/swagger-codegen
  */
-class {{classname}}Test extends \PHPUnit_Framework_TestCase
+class {{classname}}Test extends \PHPUnit\Framework\TestCase
 {
 
     /**
      * Setup before running any test case
      */
-    public static function setUpBeforeClass()
+    public static function setUpBeforeClass(): void
     {
     }
 
     /**
      * Setup before running each test case
      */
-    public function setUp()
+    public function setUp(): void
     {
     }
 
     /**
      * Clean up after running each test case
      */
-    public function tearDown()
+    public function tearDown(): void
     {
     }
 
     /**
      * Clean up after running all test cases
      */
-    public static function tearDownAfterClass()
+    public static function tearDownAfterClass(): void
     {
     }