Add build-storybook step to deployment. (#1412) [ci skip]

* Added step to deployment to build the static storybook site.

* Added step to deployment to build the static storybook site.

* using npm instead as yarn isn't installed at this point.

* reverted deployment to netlify.

.travis.yml

@@ -40,6 +40,7 @@ script:
   - './cc-test-reporter sum-coverage coverage/codeclimate.*.json'
   - './cc-test-reporter upload-coverage'
   - 'bundle exec bundle-audit check --update'
+  - yarn build-storybook
 deploy:
   provider: heroku
   api_key: '$HEROKU_AUTH_TOKEN'