Fix: upgrade to node:20-alpine to resolve File is not defined / command start not found errors

Dockerfile

@@ -1,12 +1,14 @@
-FROM node:18-alpine
+FROM node:20-alpine
 
 RUN npm install -g n8n
 
 ENV N8N_PORT=7860
-ENV N8N_ENFORCE_SETTINGS_FILE_PERMISSIONS=true
-ENV N8N_USER_FOLDER=/home/node/.n8n
+ENV N8N_ENFORCE_SETTINGS_FILE_PERMISSIONS=false
+ENV N8N_USER_FOLDER=/home/node
 
-RUN mkdir -p /home/node/.n8n && chmod -R 777 /home/node/.n8n
+RUN mkdir -p /home/node/.n8n && chown -R node:node /home/node/.n8n
+
+USER node
 
 EXPOSE 7860