Set node version on Travis (shakacode#68)

Co-authored-by: Grant Petersen-Speelman <grantspeelman@users.noreply.github.com>

.travis.yml

@@ -26,6 +26,9 @@ before_install:
   - sudo apt-get -qq update
   - sudo apt-get install -y build-essential patch ruby-dev zlib1g-dev liblzma-dev libxml2-dev
   - sudo apt-get install -y xvfb libgtk2.0-0 libnotify-dev libgconf-2-4 libnss3 libxss1 libasound2
+  - travis_retry nvm install 14.13.1
+  - node -v
+  - nvm alias default 14.13.1
 
 script:
   - bundle exec rake