fix docker build (#9971)

Author: gabreal

scripts/docker/hub/Dockerfile

@@ -18,7 +18,6 @@ RUN rm -rf /tmp/* /var/tmp/* /var/lib/apt/lists/*
 RUN groupadd -g 1000 parity \
   && useradd -m -u 1000 -g parity -s /bin/sh parity
 
-USER parity
 
 WORKDIR /home/parity
 
@@ -33,6 +32,9 @@ RUN chmod +x ./entrypoint.sh
 
 COPY scripts/docker/hub/check_sync.sh /check_sync.sh
 
+# switch to user parity here
+USER parity
+
 # setup ENTRYPOINT
 EXPOSE 5001 8080 8082 8083 8545 8546 8180 30303/tcp 30303/udp
 ENTRYPOINT ["./entrypoint.sh"]