Add publish step

.travis.yml

@@ -3,10 +3,16 @@ node_js:
   - "10"
 before_install:
   - curl -o- -L https://yarnpkg.com/install.sh | bash
-  - export PATH=$HOME/.yarn/bin:$PATH
+  - export PATH=$HOME/.yarn/bin:$(yarn global bin):$PATH
 cache:
   yarn: true
   directories:
     - node_modules
 script:
-  - yarn polkadot-dev-travis-build
+  - CI_NO_BETA=true yarn polkadot-dev-travis-build
+deploy:
+  skip_cleanup: true
+  provider: script
+  script: yarn polkadot-dev-travis-deploy
+  on:
+    branch: master