Merge pull request nestjs#1561 from kibertoad/chore/uptodate-node-versions

ci(node): fix compatibility with Node 11 and execute tests on it in CI

Author: kamilmysliwiec

.travis.yml

@@ -1,8 +1,8 @@
 language: node_js
 node_js:
   - "8"
-  - "9"
   - "10"
+  - "11"
 cache:
   directories:
     - "node_modules"