Bump nextcloud to 15.0.4-fpm

scripts/install

@@ -12,5 +12,5 @@ echo "SMTP_PASSWORD=${MAIL_PASS}" >> .env
 echo "MAIL_FROM_ADDRESS=${MAIL_USER}" >> .env
 echo "SMTP_NAME=${MAIL_USER}" >> .env
 echo "NEXTCLOUD_ADMIN_PASSWORD=${NEXTCLOUD_ADMIN_PASSWORD}" >> .env
-echo "NEXTCLOUD_VERSION=14.0.4-fpm" >> .env
+echo "NEXTCLOUD_VERSION=15.0.4-fpm" >> .env
 echo "MYSQL_VERSION=5.7" >> .env