Add github workflow to publish packages

.github/workflows/release.yml

@@ -0,0 +1,26 @@
+name: publish
+
+on:
+  release:
+    types: [created]
+
+jobs:
+  publish-gpr:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - run: npm install
+      - run: npm build
+      - uses: actions/setup-node@v1
+        with:
+          node-version: '12.x'
+          registry-url: https://npm.pkg.github.com/
+          scope: '@google-pay'
+      - name: publish
+        run: |
+          cd src/react
+          npm publish
+          cd ../src/web-component
+          npm publish
+        env:
+          NODE_AUTH_TOKEN: ${{secrets.GITHUB_TOKEN}}