Fix user id error

Signed-off-by: Nikolaos Karaolidis <nick@karaolidis.com>

Dockerfile

@@ -1,6 +1,10 @@
 FROM n8nio/n8n
 
+USER root
+
 ARG DOCKER_GID=975
 
 RUN apk add docker docker-compose
 RUN sed -i "s/^docker:x:.*$/docker:x:${DOCKER_GID}:node/" /etc/group
+
+USER node