automate npm publish (#1427)

* automate npm publish

GH workflow action which, on successful build from master branch, will publish dist/ to npm registry

J=SLAP-1353
TEST=manual

created mock repo and npm package, made a new tagged release and verified it automatically publish to npm test package.

Co-authored-by: Yen Truong <ytruong@yext.com>

.github/workflows/npm_publish.yml

@@ -0,0 +1,31 @@
+name: NPM publish on new release
+
+on: 
+  release:
+    types: [created]
+    branches: 
+      - master
+
+jobs:
+  npm-publish:
+
+    runs-on: ubuntu-latest
+
+    strategy:
+      matrix:
+        node-version: [15.x]
+
+    steps:
+    - uses: actions/checkout@v2
+    - name: Use Node.js ${{ matrix.node-version }}
+      uses: actions/setup-node@v2
+      with:
+        node-version: ${{ matrix.node-version }}
+        registry-url: https://registry.npmjs.org/
+    - run: npm ci
+    - run: npm run build
+    - run: npm run prepublishOnly
+    - run: npm publish
+    - run: npm run postpublish
+      env:
+        NODE_AUTH_TOKEN: ${{secrets.NPM_TOKEN}}

package.json

@@ -19,6 +19,9 @@
     "javascript",
     "vanilla"
   ],
+  "files": [
+    "dist"
+  ],
   "dependencies": {
     "@mapbox/mapbox-gl-language": "^0.10.1",
     "@yext/answers-core": "^1.2.0-alpha.0",