Experiencing the same issue - Signature verification failed for repomd.xml
If you want to update the rest of your system you can temporarily disable the Enpass repository on OpenSUSTE using YaST.
From the "start" menu look for YaST Software Repositories
Find Enpass, and uncheck "Enabled" at the bottom left
Press OK
Attempt to redo sudo zypper dup and you should be able to go through with the other updates