PHPUnit broken under PHP 8

[franzholz]

I want to run the tests under PHP 8.

[franz@franz-820 PHPWord ((0.18.3))]$ composer test-no-coverage
> phpunit --color=always --no-coverage
PHP Fatal error:  Uncaught Error: Call to undefined function each() in /home/franz/Github/PHPWord/vendor/phpunit/phpunit/src/Util/Getopt.php:38
Stack trace:
#0 /home/franz/Github/PHPWord/vendor/phpunit/phpunit/src/TextUI/Command.php(240): PHPUnit_Util_Getopt::getopt()
#1 /home/franz/Github/PHPWord/vendor/phpunit/phpunit/src/TextUI/Command.php(111): PHPUnit_TextUI_Command->handleArguments()
#2 /home/franz/Github/PHPWord/vendor/phpunit/phpunit/src/TextUI/Command.php(100): PHPUnit_TextUI_Command->run()
#3 /home/franz/Github/PHPWord/vendor/phpunit/phpunit/phpunit(52): PHPUnit_TextUI_Command::main()
#4 /home/franz/Github/PHPWord/vendor/bin/phpunit(110): include('/home/franz/Git...')
#5 {main}
  thrown in /home/franz/Github/PHPWord/vendor/phpunit/phpunit/src/Util/Getopt.php on line 38
Script phpunit --color=always --no-coverage handling the test-no-coverage event returned with error code 255

• PHP Version: 8.0.16
• PHPWord Version: 0.18.3