feat: upgrade to PHP 8 (#92)

* feat: upgrade to PHP 8

* fix: preload

Author: dunglas

Dockerfile

@@ -4,7 +4,7 @@
 
 
 # https://docs.docker.com/engine/reference/builder/#understand-how-arg-and-from-interact
-ARG PHP_VERSION=7.4
+ARG PHP_VERSION=8.0
 ARG CADDY_VERSION=2
 
 # "php" stage

docker/php/conf.d/symfony.prod.ini

@@ -10,5 +10,5 @@ opcache.memory_consumption = 256
 opcache.validate_timestamps = 0
 realpath_cache_size = 4096K
 realpath_cache_ttl = 600
-opcache.preload_user=www-data
-opcache.preload=/srv/app/var/cache/prod/App_KernelProdContainer.preload.php
+opcache.preload_user = www-data
+opcache.preload = /srv/app/config/preload.php