fix: set user as www-data when running cron jobs in docker's supervisord config

This prevents any ownership issue when cron tasks create cache files

docker/production/app/supervisord.conf

@@ -2,6 +2,7 @@
 nodaemon=true
 
 [program:supercronic]
+user=www-data
 command=supercronic /crontab.txt
 autostart=true
 autorestart=unexpected

docker/production/castopod/supervisord.conf

@@ -2,6 +2,7 @@
 nodaemon=true
 
 [program:supercronic]
+user=www-data
 command=supercronic /crontab.txt
 autostart=true
 autorestart=unexpected