[Dokuwiki] Better way to update static files

As explained on [this page](https://www.dokuwiki.org/install:upgrade), as the Dokuwiki files (PHP...) and user pages are "mixed" in the same directory, it is better to get the new Dokuwiki version in a separate directory, and then to copy the files.

This way, we won't have conflicts between old volumes and new files in the image. It is safer.

pica-dokuwiki/Dockerfile

@@ -7,13 +7,13 @@ COPY --chown=www-data run.sh /
 WORKDIR /var/www
 RUN apt-get update -y && \
     apt-get install -y \
-        wget \
-        tar \
-        php7.3 \
-        php7.3-fpm \
-        php7.3-gd \
-	php7.3-ldap \
-        php7.3-xml && \
+    wget \
+    tar \
+    php7.3 \
+    php7.3-fpm \
+    php7.3-gd \
+    php7.3-ldap \
+    php7.3-xml && \
     mkdir -p html /var/run/php && \
     echo "cgi.fix_pathinfo = 0;" >> /etc/php/7.3/fpm/php.ini && \
     sed -i -e "s|;daemonize\s*=\s*yes|daemonize = no|g" /etc/php/7.3/fpm/php-fpm.conf && \
@@ -22,7 +22,7 @@ RUN apt-get update -y && \
     sed -i -e "s|;listen\.group\s*=\s*|listen.group = |g" /etc/php/7.3/fpm/pool.d/www.conf && \
     sed -i -e "s|;listen\.mode\s*=\s*|listen.mode = |g" /etc/php/7.3/fpm/pool.d/www.conf && \
     wget "https://download.dokuwiki.org/src/dokuwiki/dokuwiki-stable.tgz" && \
-    tar -xzf dokuwiki-stable.tgz -C html --strip-components 1 && \
+    tar -xzf dokuwiki-stable.tgz -C update --strip-components 1 && \
     rm -f dokuwiki-stable.tgz && \
     chown -R www-data . && \
     chmod +x /run.sh && \

pica-dokuwiki/run.sh

@@ -6,6 +6,9 @@
 
 set -m
 
+echo "Copy static Dokuwiki files on top of existing pages..."
+cp -afP /var/www/{update/*,html/}
+
 php-fpm7.3 &
 nginx &