deploy pwa to S3 via Travis

.travis.yml

language: node_js
node_js:
  - '10'
dist: trusty
sudo: required
addons:
  firefox: latest
  chrome: stable
cache:
  directories:
    - node_modules
install:
  - npm install
before_script:
  - npm run lint
script:
  - xvfb-run npm run test
  - xvfb-run npm run test:integration
deploy:  
  on:    
    branch: master  
  provider: s3  
  access_key_id: $AWS_ACCESS_KEY_ID
  secret_access_key: $AWS_SECRET_ACCESS_KEY
  bucket: eostokens.app
  skip_cleanup: true
  local_dir: build/es6-bundled
after_deploy:
  - travis-ci-cloudfront-invalidation -a $AWS_ACCESS_KEY_ID -s $AWS_SECRET_ACCESS_KEY -c $CLOUDFRONT_DISTRIBUTION_ID -i '/*' -b $TRAVIS_BRANCH -p $TRAVIS_PULL_REQUEST -o 'master'