change link to one with restriction

Author: marcobarilari

doc/iMac_in_the_lab.md

@@ -1,5 +1,5 @@
 There are currently (update: July 2024) 4 iMacs in the lab.
-If you want information about a computer or iMac in the lab, please consult this [excel sheet](https://docs.google.com/spreadsheets/d/1U5_rjj5mzXzh_8bLA_Rx3FmDdpYIUx2Y_z8SJPnKTHg/edit?gid=0#gid=0).
+If you want information about a computer or iMac in the lab, please consult this [excel sheet](https://docs.google.com/spreadsheets/d/1U5_rjj5mzXzh_8bLA_Rx3FmDdpYIUx2Y_z8SJPnKTHg/edit?usp=sharing).
 
 It is good practice to create your own account on the computer in order not to install on the same account a different version of Matlab Tools.