Listed @ember/render-modifiers as a dependency

[ijlee2]

Background

Because ember-modal-dialog uses {{did-insert}} and {{will-destroy}} modifiers, but didn't list @ember/render-modifiers as a dependency, it's possible that a consuming project can run into an error (more so, when that project lists dependencies correctly).

Here's the error message that I got from running a rendering test ([email protected] used):

Attempted to resolve `did-insert`, which was expected to be a modifier, but nothing was found.

[lukemelia]

Addressing this via #404

[lukemelia]

Thanks!