ensure npm version has been updated

Author: Brocco

.travis.yml

@@ -53,6 +53,7 @@ before_install:
   - if [[ "$TRAVIS_OS_NAME" == "linux" ]]; then sh -e /etc/init.d/xvfb start; fi
   - if [[ "$TRAVIS_OS_NAME" == "linux" ]]; then export CHROME_BIN=chromium-browser; fi
   - if [[ "$TRAVIS_OS_NAME" == "linux" ]]; then echo "--no-sandbox" > ~/.config/chromium-flags.conf; fi
+  - npm install -g npm
   - npm install -g yarn
   - yarn config set spin false
   - yarn config set progress false