chore(linux): drop ubuntu focal support (#261) (#262)

Co-authored-by: Kieran <[email protected]>

Author: github-actions[bot]

.github/workflows/linux-verify.yml

@@ -21,7 +21,6 @@ jobs:
         os:
           - quay.io/centos/centos:stream9
           - quay.io/centos/centos:stream10
-          - ubuntu:20.04
           - ubuntu:22.04
           - ubuntu:24.04
           - debian:11

templates/linux/setup.sh

@@ -5,7 +5,7 @@ version="0.6.0"
 
 supported="The following Linux OSs are supported, on x86_64 only:
     * RHEL 9, 10
-    * Ubuntu 20.04 LTS (focal), 22.04 LTS (jammy) & 24.04 LTS (noble)
+    * Ubuntu 22.04 LTS (jammy) & 24.04 LTS (noble)
     * Debian 11 (bullseye) & 12 (bookworm)"
 
 usage="Usage: curl -LsS https://raw.githubusercontent.com/supportpal/helpdesk-install/master/templates/linux/setup.sh | sudo bash -s -- [options]
@@ -107,7 +107,7 @@ identify_os() {
       trusty) error 'Ubuntu version 14.04 LTS has reached End of Life and is no longer supported.' ;;
       xenial) error 'Ubuntu version 16.04 LTS has reached End of Life and is no longer supported.' ;;
       bionic) error 'Ubuntu version 18.04 LTS has reached End of Life and is no longer supported.' ;;
-      focal) ;;
+      focal) error 'Ubuntu version 20.04 LTS has reached End of Life and is no longer supported.' ;;
       jammy) ;;
       noble) ;;
       *) error "Detected Ubuntu but version ($os_version) is not supported." "Only Ubuntu LTS releases are supported." ;;