Updates travis.yml file

.travis.yml

@@ -3,13 +3,13 @@ sudo: false
 
 node_js:
   - '6'
+
 cache:
-  directories:
-  - "$HOME/.npm"
+  yarn: true
 
 env:
-  - EMBER_TRY_SCENARIO=ember-lts-2.4
   - EMBER_TRY_SCENARIO=ember-lts-2.8
+  - EMBER_TRY_SCENARIO=ember-lts-2.12
   - EMBER_TRY_SCENARIO=ember-release
   - EMBER_TRY_SCENARIO=ember-beta
   - EMBER_TRY_SCENARIO=ember-canary
@@ -18,18 +18,19 @@ env:
 matrix:
   fast_finish: true
   allow_failures:
-  - env: EMBER_TRY_SCENARIO=ember-canary
+    - env: EMBER_TRY_SCENARIO=ember-canary
 
 before_install:
-- npm config set spin false
-- npm install -g phantomjs-prebuilt
-- phantomjs --version
+  - curl -o- -L https://yarnpkg.com/install.sh | bash
+  - export PATH=$HOME/.yarn/bin:$PATH
+  - yarn global add phantomjs-prebuilt
+  - phantomjs --version
 
 install:
-  - npm install
+  - yarn install --no-lockfile --non-interactive
 
 script:
-  - node_modules/.bin/ember try:one $EMBER_TRY_SCENARIO test --skip-cleanup
+  - node_modules/.bin/ember try:one $EMBER_TRY_SCENARIO --skip-cleanup
 
 notifications:
   email: false