Security to a channel change

It is supposed to be a deployment change.

Here I assume that you have mentioned about target of the channel as security. Normally it is a deployment change but If planned ahead and the security group is existing in your environment, it could be handled as a configuration change.

If you use SAIL dashboard (Such as SAIL report or SAIL records), then you can dynamically target channels at runtime using any of the existing group or groups/users or Roles that are configured at runtime.