bug symfony#52846 [PhpUnitBridge] run composer update for compatibility with PHPUnit versions shipping composer.lock (xabbuh)

This PR was merged into the 5.4 branch.

Discussion
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[PhpUnitBridge]  run composer update for compatibility with PHPUnit versions shipping composer.lock

| Q             | A
| ------------- | ---
| Branch?       | 5.4
| Bug fix?      | yes
| New feature?  | no
| Deprecations? | no
| Issues        | Fix symfony#52844
| License       | MIT

Commits
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763add7 run composer update for compatibility with PHPUnit versions shipping composer.lock

Author: xabbuh

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

@@ -262,7 +262,7 @@
     putenv("COMPOSER_ROOT_VERSION=$PHPUNIT_VERSION.99");
     $q = '\\' === \DIRECTORY_SEPARATOR && \PHP_VERSION_ID < 80000 ? '"' : '';
     // --no-suggest is not in the list to keep compat with composer 1.0, which is shipped with Ubuntu 16.04LTS
-    $exit = proc_close(proc_open("$q$COMPOSER install --no-dev --prefer-dist --no-progress $q", [], $p, getcwd()));
+    $exit = proc_close(proc_open("$q$COMPOSER update --no-dev --prefer-dist --no-progress $q", [], $p, getcwd()));
     putenv('COMPOSER_ROOT_VERSION'.(false !== $prevRoot ? '='.$prevRoot : ''));
     if ($prevCacheDir) {
         putenv("COMPOSER_CACHE_DIR=$prevCacheDir");