Github Action to publish to NPM (#34)

* Workflow to publish to NPM

* Tweak some workflow settings

.github/workflows/npm-publish.yml

@@ -0,0 +1,30 @@
+# This workflow will run tests using node and then publish a package to NPM
+
+name: Node.js Package
+
+on:
+  workflow_dispatch
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions/setup-node@v1
+        with:
+          node-version: 12
+      - run: npm install
+      - run: npm run test
+
+  publish-npm:
+    needs: build
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions/setup-node@v1
+        with:
+          node-version: 12
+          registry-url: https://registry.npmjs.org/
+      - run: npm publish
+        env:
+          NODE_AUTH_TOKEN: ${{secrets.npm_token}}