Remote src error on Ansible 2.8.3

Resolve error message on Ansible 2.8.3 where it expects remote_src to be set to search the remote host for the src file.

tasks/main.yml

@@ -21,6 +21,7 @@
 
 - name: backup APT sources
   copy:
+    remote_src: yes
     src: /etc/apt/sources.list
     dest: /etc/apt/sources.list.cu
     force: no