Removes support for Ubuntu 20.04

Ubuntu 20.04 is no longer supported.

Updates the supported OS list in the installer script to reflect this change.

install/hst-install.sh

@@ -83,9 +83,7 @@ no_support_message() {
 	echo "Hestia Control Panel. Officially supported releases:"
 	echo "****************************************************"
 	echo "  Debian 11, 12"
-	echo "  Ubuntu 20.04, 22.04, 24.04 LTS"
-	# Commenting this out for now
-	# echo "  AlmaLinux, EuroLinux, Red Hat EnterPrise Linux, Rocky Linux 8,9"
+	echo "  Ubuntu 22.04, 24.04 LTS"
 	echo ""
 	exit 1
 }
@@ -144,7 +142,7 @@ check_wget_curl() {
 
 # Check for supported operating system before proceeding with download
 # of OS-specific installer, and throw error message if unsupported OS detected.
-if [[ "$release" =~ ^(11|12|20.04|22.04|24.04)$ ]]; then
+if [[ "$release" =~ ^(11|12|22.04|24.04)$ ]]; then
 	check_wget_curl $*
 # elif [[ -e "/etc/redhat-release" ]] && [[ "$release" =~ ^(8|9)$ ]]; then
 # 	check_wget_curl $*