Compatibility with Composer v2.1.0 and later

[ondrejmirtes]

Bug report

Question	Answer
Box version	Box version 3.11.1@83567c4 2021-01-02 09:53:51 UTC <!-- (box.phar -V or `composer show
PHP version	8.0.3
Platform with version	e.g. Ubuntu/Windows/MacOS
Github Repo	-

Composer v2.1.0 started including vendor/composer/installed.php file in InstalledVersions.php. This file is new and isn't whitelisted by Box (or maybe PHP-Scoper) to be included in the final PHAR, leading to errors like:

PHP Fatal error:  require(): Failed opening required 'phar:///home/runner/work/phpstan/phpstan/extension/vendor/phpstan/phpstan/phpstan.phar/vendor/composer/installed.php' (include_path='.:/usr/share/php') in phar:///home/runner/work/phpstan/phpstan/extension/vendor/phpstan/phpstan/phpstan.phar/vendor/composer/InstalledVersions.php on line 319

[ondrejmirtes]

There was a similar problem before: #484

[theofidry]

Should be now working with 3.15