Hello proteas,
thanks for your report, a fix for this issue will be available asap.
At the moment you can still install it by running the following commands :
composer update create-project --no-plugins --no-scripts -n -s dev erik-dubbelboer/php-redis-admin /var/www/22222/htdocs/cache/redis/phpRedisAdmin
sudo chown -R www-data:www-data /var/www/22222/htdocs/cache/redis