fixes docker build

- composer package prestissimo is deprecated as composer got faster
- `composer update` should not be required as there is a `composer.lock`, actually it was the cause for breaking docker builds as an upstream package had a broken version string in it's requirerements. Using fixed package versions prevents these kinds of problems in future.

contrib/docker/Dockerfile.apache

@@ -92,11 +92,9 @@ RUN curl -o /tmp/composer-setup.php https://getcomposer.org/installer \
 COPY . /var/www/
 # for detail why storage is copied this way, pls refer to https://github.com/pixelfed/pixelfed/pull/2137#discussion_r434468862
 RUN cp -r storage storage.skel \
-  && composer global require hirak/prestissimo --prefer-dist --no-interaction --no-ansi --no-suggest \
   && composer install --prefer-dist --no-interaction --no-ansi --optimize-autoloader \
-  && composer update --prefer-dist --no-interaction --no-ansi \
-  && composer global remove hirak/prestissimo --no-interaction --no-ansi \
-  && rm -rf html && ln -s public html
+  && rm -rf html && ln -s public html \
+  && chown -R www-data:www-data /var/www
 VOLUME /var/www/storage /var/www/bootstrap
 
 CMD ["/var/www/contrib/docker/start.apache.sh"]