Add a note about gitea port 2222

pottwal.yml

@@ -37,6 +37,8 @@
       msg: "Gitea data dir is missing, please restore from the backup!"
     when: not gitea_dir.stat.exists
 
+  # If port 2222 is changed here, it must also be adapted
+  # in the gitea config file (see application volume)!!
   - name: Setup the docker container for gitea
     docker_container:
       name: gitea