alex devdep not installed when using yarn

[nickschot]

This addon only seems to provide alex as a devdep. When using yarn in the consuming addon or application, this dependency is not installed resulting in a Cannot find module 'alex'.

Possible solutions:

1. Add as dependency instead of devDependency.
2. Add blueprint to add alex to the consuming app/addon's dependencies.
3. Add instructions to readme to install alex.

[yohanmishkin]

Hey @nickschot ! Thanks for submitting this issue!

I took at peek at your failing CI logs and it looks like the issue your having is because your addon is running with node v6 and ember-cli-alex has "8.* || >= 10.*" listed for compatible node versions.

Does that look right to you?