Aligned Travis configuration after switching to Yarn. See...

Aligned Travis configuration after switching to Yarn. See https://github.com/ckeditor/ckeditor5/issues/1214.

.travis.yml

@@ -9,22 +9,23 @@ addons:
       - google-chrome-stable
 language: node_js
 node_js:
-- '8'
+  - '8'
 cache:
-- node_modules
+  yarn: true
 branches:
   except:
     - stable
 before_install:
-- export DISPLAY=:99.0
-- sh -e /etc/init.d/xvfb start
-- npm config set package-lock false
-- npm i -g npm@^5.7.1
+  - 'export DISPLAY=:99.0'
+  - sh -e /etc/init.d/xvfb start
+  - npm i -g yarn
 install:
-- npm install @ckeditor/ckeditor5-dev-tests
-- ckeditor5-dev-tests-install-dependencies
+  - yarn add @ckeditor/ckeditor5-dev-tests
+  - ckeditor5-dev-tests-install-dependencies
 script:
-- ckeditor5-dev-tests-travis
+  - ckeditor5-dev-tests-travis
+after_success:
+  - ckeditor5-dev-tests-save-revision
 env:
   global:
     - secure: 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