Update startup.sh - harmonise Jupyter port with docker port to 8888

desktop/km3book/startup.sh

@@ -44,4 +44,4 @@ EOF
 
 sudo docker build -t km3book:1.0.0 -f Dockerfile .
 chown -R $THE_USER $NOTEBOOK_DIR
-sudo docker run -p 8000:8888 -p 2200:22 -u $USER_ID -v $NOTEBOOK_DIR:$NOTEBOOK_DIR -it km3book:1.0.0
+sudo docker run -p 8888:8888 -p 2200:22 -u $USER_ID -v $NOTEBOOK_DIR:$NOTEBOOK_DIR -it km3book:1.0.0