Increase (double) opcache string buffer size (#1702)

* Increase (double) opcache string buffer size (debian)

This fixes https://github.com/nextcloud/docker/issues/1692

* Increase (double) opcache string buffer size (alpine)

This fixes #1692

Dockerfile-alpine.template

@@ -79,7 +79,7 @@ ENV PHP_MEMORY_LIMIT 512M
 ENV PHP_UPLOAD_LIMIT 512M
 RUN { \
         echo 'opcache.enable=1'; \
-        echo 'opcache.interned_strings_buffer=8'; \
+        echo 'opcache.interned_strings_buffer=16'; \
         echo 'opcache.max_accelerated_files=10000'; \
         echo 'opcache.memory_consumption=128'; \
         echo 'opcache.save_comments=1'; \

Dockerfile-debian.template

@@ -93,7 +93,7 @@ RUN set -ex; \
 # see https://docs.nextcloud.com/server/latest/admin_manual/installation/server_tuning.html#enable-php-opcache
 RUN { \
         echo 'opcache.enable=1'; \
-        echo 'opcache.interned_strings_buffer=8'; \
+        echo 'opcache.interned_strings_buffer=16'; \
         echo 'opcache.max_accelerated_files=10000'; \
         echo 'opcache.memory_consumption=128'; \
         echo 'opcache.save_comments=1'; \