Ubuntu 20 Deprecation changes (#11748)

* Ubuntu 20 Deprecation updates

* Updating .md files

* Update announcement.yml

* Update bug-report.yml

* Update tool-request.yml

* Updating merge conflicts

* Updating .md files

* Updating merge conflicts

* Resolved merge conflicts

---------

Co-authored-by: Prabhat kumar <prabhatkumar59@Prabhats-Laptop.local>

images/ubuntu/scripts/build/install-container-tools.sh

@@ -17,15 +17,6 @@ else
     install_packages=(podman=3.4.4+ds1-1ubuntu1 buildah skopeo)
 fi
 
-# Packages is available in the official Ubuntu upstream starting from Ubuntu 21
-if is_ubuntu20; then
-    REPO_URL="https://download.opensuse.org/repositories/devel:/kubic:/libcontainers:/stable/xUbuntu_$(lsb_release -rs)"
-    GPG_KEY="/usr/share/keyrings/devel_kubic_libcontainers_stable.gpg"
-    REPO_PATH="/etc/apt/sources.list.d/devel:kubic:libcontainers:stable.list"
-
-    curl -fsSL "${REPO_URL}/Release.key" | gpg --dearmor -o $GPG_KEY
-    echo "deb [arch=amd64 signed-by=$GPG_KEY] ${REPO_URL}/ /" > $REPO_PATH
-fi
 
 if is_ubuntu22; then
     # Install containernetworking-plugins for Ubuntu 22
@@ -39,13 +30,4 @@ apt-get install ${install_packages[@]}
 mkdir -p /etc/containers
 printf "[registries.search]\nregistries = ['docker.io', 'quay.io']\n" | tee /etc/containers/registries.conf
 
-if is_ubuntu20; then
-    # Remove source repo
-    rm $GPG_KEY
-    rm $REPO_PATH
-
-    # Document source repo
-    echo "containers $REPO_URL" >> $HELPER_SCRIPTS/apt-sources.txt
-fi
-
 invoke_tests "Tools" "Containers"