chore: upgrade Node.js to latest LTS (10.x)

Author: gkalpak

.travis.yml

@@ -3,7 +3,8 @@ dist: trusty
 
 language: node_js
 node_js:
-  - '4.4'
+  - 6  # Because `[email protected]` requires 6.9+.
+  - 10
 
 before_script:
   - export DISPLAY=:99.0

scripts/private/README.md

@@ -14,24 +14,24 @@ and run the unit/e2e tests for all the steps.
 ## Demo Pages on GitHub
 
 We use GitHub to host a live demo of each step. This is stored in the gh-pages branch of the git
-repository. The folder structure of this branch is different to the main master branch. Each step is 
+repository. The folder structure of this branch is different to the main master branch. Each step is
 copied to its own folder.
 
-- **update-gh-pages.sh**: Run this script to copy changes to the tutorial steps and bower 
+- **update-gh-pages.sh**: Run this script to copy changes to the tutorial steps and bower
   dependencies over to the gh-pages branch and (if all tests pass) push to the remote gh-pages
   branch on GitHub.
 
 ### Auto-updating Demo Pages from CI
 
 There is a Jenkins job that runs periodically and executes `jenkins.sh`.
 
-- **jenkins.sh**: This script will set the Node.js version to 4.x (using `nvm`), will run all the
+- **jenkins.sh**: This script will set Node.js to an appropriate version (using `nvm`), will run all
   the tests and update the demo pages (using `update-gh-pages.sh`).
   (You shouldn't need to run this script manually.)
 
 ## Pushing to GitHub
 
-Each step in the tutorial is one commit in the git repository. Each step is also identified by a git 
+Each step in the tutorial is one commit in the git repository. Each step is also identified by a git
 tag. Any changes to a step requires the commits to be rebased and retagged.
 
 Since it is likely that rebasing and retagging the commits will cause the local git repository to

scripts/private/jenkins.sh

@@ -3,8 +3,8 @@
 # Install nvm for this shell
 source ~/.nvm/nvm.sh
 
-# Use Node.js v4.x
-nvm install 4
+# Use Node.js v8.x
+nvm install 10
 
 # Run all tests and publish steps on gh-pages
 scripts/private/update-gh-pages.sh