add npm tag --next workflow to dev branch

Author: bmschmidt

.github/workflows/npm-publish.yml

@@ -0,0 +1,21 @@
+name: Publish to npm
+
+on:
+  push:
+    branches:
+      - dev
+
+jobs:
+  publish:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions/setup-node@v2
+        with:
+          node-version: '14.x'
+          registry-url: 'https://registry.npmjs.org'
+      - run: npm ci
+      - run: npm version prerelease --preid=beta
+      - run: npm publish --tag next
+        env:
+          NODE_AUTH_TOKEN: ${{ secrets.NPM_TOKEN }}