Merge #2331

2331: Add data/fetchmail to mkdir command r=mergify[bot] a=ghostwheel42

## What type of PR?

documentation

## What does this PR do?

### Related issue(s)

closes #2314


Co-authored-by: Alexander Graf <ghostwheel42@users.noreply.github.com>

setup/flavors/stack/setup.html

@@ -4,7 +4,7 @@
 <p>Docker Stack expects a project file, named <code>docker-compose.yml</code>
 in a project directory. First create your project directory.</p>
 
-<pre><code>mkdir -p {{ root }}/{redis,certs,data,dkim,mail,mailqueue,overrides/rspamd,overrides/postfix,overrides/dovecot,overrides/nginx,filter,dav,webmail}
+<pre><code>mkdir -p {{ root }}/{redis,certs,data,data/fetchmail,dkim,mail,mailqueue,overrides/rspamd,overrides/postfix,overrides/dovecot,overrides/nginx,filter,dav,webmail}
 </pre></code>
 
 <p>Then download the project file. A side configuration file makes it easier