Add workflow

.github/workflows/publish_package.yml

@@ -0,0 +1,19 @@
+name: Publish package
+on:
+  push:
+    branches:
+      - main
+jobs:
+  publish:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions/setup-node@v1
+        with:
+          node-version: 12
+          registry-url: https://npm.pkg.github.com/
+      - run: npm ci
+      - run: npm run build
+      - run: npm publish
+        env:
+          NODE_AUTH_TOKEN: ${{ secrets.npm_publish }}