Bump up node version for travis

Author: praneshr

.travis.yml

@@ -1,7 +1,7 @@
 language: node_js
-node_js: 8
+node_js: 12
 before_script: yarn build
-after_success: "./publish-examples.sh"
+after_success: './publish-examples.sh'
 deploy:
   skip_cleanup: true
   provider: npm