Revert "tmp: add liburcu6 repository for CUDA 20.04 repository"

This reverts commit e7216ad.

Author: Kenji Miyake

ansible/roles/cuda/tasks/main.yaml

@@ -8,22 +8,6 @@
   register: cuda_architecture
   changed_when: false
 
-- name: (tmp for Ubuntu 22.04) Add liburcu6 repository into sources.list for amd64
-  become: true
-  ansible.builtin.apt_repository:
-    repo: deb http://archive.ubuntu.com/ubuntu focal main restricted
-    filename: focal
-    state: present
-  when: cuda_architecture.stdout == "x86_64"
-
-- name: (tmp for Ubuntu 22.04) Add liburcu6 repository into sources.list for arm64
-  become: true
-  ansible.builtin.apt_repository:
-    repo: deb http://ports.ubuntu.com/ubuntu-ports focal main restricted
-    filename: focal
-    state: present
-  when: cuda_architecture.stdout == "aarch64"
-
 - name: Remove old /etc/apt/sources.list.d/cuda.list
   become: true
   ansible.builtin.file: