Auto merge of #1730 - Turbo87:dep-lint, r=locks

Use `ember-cli-dependency-lint` to warn about duplicate addons

see https://github.com/salsify/ember-cli-dependency-lint#motivation for more information

Author: bors

.travis.yml

@@ -65,6 +65,7 @@ matrix:
       before_script: skip
       script:
         - npm run lint:js
+        - npm run lint:deps
         - npm test
     - rust: beta
       script:

package-lock.json

@@ -18,6 +18,7 @@
   "scripts": {
     "build": "ember build",
     "lint:js": "eslint . --cache",
+    "lint:deps": "ember dependency-lint",
     "prettier": "prettier --write '{app,tests,mirage}/**/*.js'",
     "start": "ember serve",
     "start:live": "ember serve --proxy https://crates.io",
@@ -37,6 +38,7 @@
     "ember-cli-clipboard": "^0.9.0",
     "ember-cli-code-coverage": "^1.0.0-beta.4",
     "ember-cli-dependency-checker": "^2.0.1",
+    "ember-cli-dependency-lint": "^1.1.3",
     "ember-cli-htmlbars": "^2.0.3",
     "ember-cli-htmlbars-inline-precompile": "^1.0.2",
     "ember-cli-inject-live-reload": "1.6.1",