ember-ajax does not work with Ember 3.8 when transpiling to ES5

[boris-petrov]

Original issue in Ember.js.

Babel cannot transpile to ES5 extending from some built-in types which means that extending EmberError won't work any more in ES5 since Ember 3.8 because it is the same as Error.

[Turbo87]

as mentioned on Discord, the way I would propose to fix this is:

1. update ember-cli-babel to v7 and check if that fixes the test suite
2. update the Node.js compatibility claims in package.json and PR it (see #432)
3. open a PR for 1) which also updates the "Compatibility" section, adding CLI 2.13+ requirement (see #433)
4. get it released as v5.0.0
5. update the app blueprint in Ember CLI
6. get that released as v3.8.1