Add Travis CI deploy step for release tags (#1558)

* Add sample Travis CI deploy step to tag commits on master and push that

TODO: should find the version number from ./package.json

* Get git name and email for tagging from env

* Extract current version number from manifest

Attempt...

* Update .travis.yml

Fix whitespace issue and command error

* Switch sed order and escape double qoutes

* Replace curly braces by parentheses

* Test deploy of release tag to GitHub

* Convert deploy back to script

And update actual deploy step commands

* Remove test deploy stage

* Fix api_key value and remove leftover configuration

.travis.yml

@@ -22,7 +22,19 @@ jobs:
         - npm run test
 
     - stage: deploy
-      name: "NPM Package"
+      name: "Git tag"
+      if: branch = master
+
+      before_deploy:
+        - git config --local user.name "$GITHUB_USERNAME"
+        - git config --local user.email "$GITHUB_EMAIL"
+        - export PACKAGE_VERSION=$(cat package.json | grep 'version' | sed 's/[ \",:]//g' | sed 's/version//')
+        - git tag $PACKAGE_VERSION
+      deploy:
+        provider: releases
+        api_key: "$GITHUB_TOKEN"
+        skip_cleanup: true
+    - name: "NPM Package"
       language: node_js
       node_js: 8
       if: branch = master