Update to phpunit 8

Author: TysonAndre

composer.json

@@ -6,7 +6,7 @@
         "php": ">=7.2"
     },
     "require-dev": {
-        "phpunit/phpunit": "^7.5.20"
+        "phpunit/phpunit": "^8.5.15"
     },
     "license": "MIT",
     "authors": [

tests/api/NodeApiTest.php

@@ -25,7 +25,7 @@ function a () {
 
     public static $sourceFileNode;
 
-    public static function setUpBeforeClass() {
+    public static function setUpBeforeClass(): void {
         $parser = new Parser();
         self::$sourceFileNode = $parser->parseSourceFile(self::FILE_CONTENTS);
         parent::setUpBeforeClass();