Run tests also on lts and last stable version of nodejs

.travis.yml

@@ -1,7 +1,9 @@
 dist: trusty
 language: node_js
 node_js:
- - "10"
+  - 10
+  - lts/*
+  - node
 before_install:
   - npm i -g npm
 before_script:
@@ -12,9 +14,9 @@ before_script:
   - "sh -e /etc/init.d/xvfb start"
   - sleep 5
 script:
-- npm run test:e2e
-- npm run test:unit
-- grunt
+  - npm run test:e2e
+  - npm run test:unit
+  - grunt
 after_script:
   - npm list
 cache: