run composer update for compatibility with PHPUnit versions shipping composer.lock

Author: xabbuh

Diff for: 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");