Fixes problem to install latest version of QGIS.

install_ubuntu_details.sh

@@ -706,11 +706,14 @@ sudo wget -O /etc/apt/keyrings/qgis-archive-keyring.gpg https://download.qgis.or
 sudo geany /etc/apt/sources.list.d/qgis.sources
 # Types: deb deb-src
 # URIs: https://qgis.org/debian
-# Suites: your-distributions-codename
+# Suites: focal # <----- Puts `lsb_release -cs` -> focal
 # Architectures: amd64
 # Components: main
 # Signed-By: /etc/apt/keyrings/qgis-archive-keyring.gpg
 
+# To get the value for `Suites` field.
+lsb_release -cs
+
 # Update and install.
 sudo apt update
 sudo apt install qgis qgis-plugin-grass