Add update script

update.sh

+#!/bin/bash
+
+cd $HOME
+if [[ ! -d workshop_preparation ]]; then
+    git clone https://git.noc.ruhr-uni-bochum.de/potentials-workshop-2022/workshop_preparation.git
+fi
+cd workshop_preparation
+
+echo "Force update of notebooks: This will overwrite your changes, backup now!";
+echo "Press enter to continue: "
+
+if read -r; then
+    git checkout main -- '*'
+    git pull --force
+fi