minor #33318 [PhpUnitBridge] Bump SYMFONY_PHPUNIT_VERSION (ro0NL)

This PR was merged into the 4.4 branch.

Discussion
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[PhpUnitBridge] Bump SYMFONY_PHPUNIT_VERSION

| Q             | A
| ------------- | ---
| Branch?       | 4.4
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | no     <!-- see https://symfony.com/bc -->
| Deprecations? | no
| Tests pass?   | yes    <!-- please add some, will be required by reviewers -->
| Fixed tickets | #...   <!-- #-prefixed issue number(s), if any -->
| License       | MIT
| Doc PR        | symfony/symfony-docs#... <!-- required for new features -->

:wave: here we are again :)

i was wondering... cant we just install the latest minor by default, thus `SYMFONY_PHPUNIT_VERSION=8`? There should be no BC breaks, and would reduce the maintenance to one major bump, once a year ... isnt it? :thinking:

Commits
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9cbd0e8 [PhpUnitBridge] Bump SYMFONY_PHPUNIT_VERSION

src/Symfony/Bridge/PhpUnit/bin/simple-phpunit.php

@@ -49,7 +49,7 @@
 
 if (PHP_VERSION_ID >= 70200) {
     // PHPUnit 8 requires PHP 7.2+
-    $PHPUNIT_VERSION = $getEnvVar('SYMFONY_PHPUNIT_VERSION', '8.2');
+    $PHPUNIT_VERSION = $getEnvVar('SYMFONY_PHPUNIT_VERSION', '8.3');
 } elseif (PHP_VERSION_ID >= 70100) {
     // PHPUnit 7 requires PHP 7.1+
     $PHPUNIT_VERSION = $getEnvVar('SYMFONY_PHPUNIT_VERSION', '7.5');