[maintenance]Update Dockerfile-nginx to the PHP 8

[Ferror]

it's kinda time to upgrade the PHP-PM docker to PHP 8.0 and the latest PHP-PM version. I decided to not use Multi-Stage with the composer as the pcntl extension is required and ignoring platform requirements may result in future problems.

#17 1.099 Your requirements could not be resolved to an installable set of packages.
#17 1.099 
#17 1.099   Problem 1
#17 1.099     - Root composer.json requires php-pm/php-pm dev-master -> satisfiable by php-pm/php-pm[dev-master].
#17 1.099     - php-pm/php-pm dev-master requires ext-pcntl * -> it is missing from your system. Install or enable PHP's pcntl extension.
#17 1.099 
#17 1.099 To enable extensions, verify that they are enabled in your .ini files:
#17 1.099     - /usr/local/etc/php/php-cli.ini
#17 1.099     - /usr/local/etc/php/conf.d/docker-php-ext-bz2.ini
#17 1.099     - /usr/local/etc/php/conf.d/docker-php-ext-sodium.ini
#17 1.099     - /usr/local/etc/php/conf.d/docker-php-ext-zip.ini
#17 1.099 You can also run `php --ini` in a terminal to see which files are used by PHP in CLI mode.
#17 1.099 Alternatively, you can run Composer with `--ignore-platform-req=ext-pcntl` to temporarily ignore these required extensions.