(ci) Update Publish Workflow (#164)

Update publish workflow to only run the `npm publish` command when we
create the Github Release (ignore updates). Include small change for
readability.

Author: elfrank

.github/workflows/publish_package.yml

@@ -1,4 +1,6 @@
-on: release
+on:
+  release:
+    types: [published]
 name: Publish Package
 jobs:
   publish-npm:
@@ -9,6 +11,7 @@ jobs:
         with:
           node-version: 10.15.3
           registry-url: https://registry.npmjs.org/
-      - run: npm install && npm publish --access public
+      - run: npm install
+      - run: npm publish --access public
         env:
           NODE_AUTH_TOKEN: ${{secrets.npm_token}}