Merge brabch ckeditor5/t/1214

Internal: Switched to Yarn. See ckeditor/ckeditor5#1214.

.travis.yml

@@ -9,14 +9,15 @@ addons:
     - google-chrome-stable
 language: node_js
 node_js:
-- '6'
+- '8'
 cache:
-- node_modules
+  yarn: true
 before_install:
 - export DISPLAY=:99.0
 - sh -e /etc/init.d/xvfb start
+- npm i -g yarn
 install:
-- npm install @ckeditor/ckeditor5-dev-tests
+- yarn add @ckeditor/ckeditor5-dev-tests
 - ckeditor5-dev-tests-install-dependencies
 script:
 - ckeditor5-dev-tests-travis
@@ -26,3 +27,6 @@ env:
   global:
   - secure: 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
   - secure: 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
+branches:
+  except:
+  - stable