Update code server on OEL8

Download the corresponding version:

wget https://github.com/coder/code-server/releases/download/v4.91.0/code-server-4.91.0-amd64.rpm

rpm -Uvh code-server-4.91.0-amd64.rpm

Restart code-server:

systemctl stop code-server@$USER
systemctl start code-server@$USER

This should normally work in all RedHat based distributions.