build: Upgrade to PHPUnit 8.5

Author: DannyvdSluijs

composer.json

@@ -34,7 +34,7 @@
     "require-dev": {
         "friendsofphp/php-cs-fixer": "~2.2.20 || ~2.19.0",
         "json-schema/json-schema-test-suite": "1.2.0",
-        "phpunit/phpunit": "^4.8.35"
+        "phpunit/phpunit": "^8.5"
     },
     "extra": {
         "branch-alias": {

phpunit.xml.dist

@@ -1,14 +1,15 @@
 <?xml version="1.0" encoding="UTF-8"?>
 
-<phpunit backupGlobals="false"
+<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:noNamespaceSchemaLocation="vendor/phpunit/phpunit/phpunit.xsd"
+         backupGlobals="false"
          backupStaticAttributes="false"
          colors="true"
          convertErrorsToExceptions="true"
          convertNoticesToExceptions="true"
          convertWarningsToExceptions="true"
          processIsolation="false"
          stopOnFailure="false"
-         syntaxCheck="false"
          bootstrap="vendor/autoload.php"
          verbose="true"
 >