What problem does this address?

The plugin should not use the core wp/v2 namespace

What is your proposed solution?

@TimothyBJacobs suggested wp-notifications/v1 in #179, which sounds good.

Another thought is to stick with the "Notify" name and do wp-notify/v1, this is shorter, and if this does merge into core, the "wp-notify" namespace/prefix used everywhere would simply become "wp".