Move ember-cli-typescript to dependencies

[davewasmer]

Right now, ember-cli-typescript is listed as a devDependency.

However, index.js references it directly.

Because it is currently listed in devDependencies and not dependencies, npm/yarn won't ensure that ember-test-helpers gets it's own copy, leading to the above linked line failing in certain cases.

I seems rather difficult to expose this - I suspect it had something to do with multiple versions of ember-cli-typescript being present in a monorepo I was working on.

[rwjblue]

We should not be directly depending on ember-cli-typescript (devDep is correct). Instead we should fix the conditional to be something like:

    if (this.isDevelopingAddon()) {
      // eslint-disable-next-line node/no-unpublished-require
      let TypescriptOutput = require('ember-cli-typescript/js/lib/incremental-typescript-compiler/typescript-output-plugin');
      // eslint-disable-next-line node/no-unpublished-require
      let MergeTrees = require('broccoli-merge-trees');

      let tsTree = debugTree(
        new TypescriptOutput(compiler, {
          'addon-test-support/@ember/test-helpers': '@ember/test-helpers',
        }),
        'addon-test-support:ts'
      );

      input = debugTree(new MergeTrees([input, tsTree]), 'addon-test-support:merged');
    }

[davewasmer]

Closing in favor of #610