Just noted that the CI action for 20.04 always fails when trying to install fish. I don't have the time to go after this today, but I'll take a look once I find the time if nobody beats me to it.
This started working again without any changes from our side. I'm suspecting an upstream issue that has been solved in the meantime. I'll keep an eye out for it and close it if it doesn't come up again.
Just noted that the CI action for 20.04 always fails when trying to install fish. I don't have the time to go after this today, but I'll take a look once I find the time if nobody beats me to it.