tag and publish on npm

this is just a sketch, and we need to set NPM_AUTH_TOKEN

.github/workflows/npmpublish.yml

@@ -0,0 +1,26 @@
+name: tag and publish on commit with text "Release x.y.z"
+
+on:
+  push:
+    branches:
+      - master # Change this to your default branch
+jobs:
+  npm-publish:
+    name: npm-publish
+    runs-on: ubuntu-latest
+    steps:
+    - name: Checkout repository
+      uses: actions/checkout@master
+    - name: Set up Node.js
+      uses: actions/setup-node@master
+      with:
+        node-version: 10.0.0
+    - name: Publish if version has been updated
+      uses: pascalgn/npm-publish-action@51fdb4531e99aac1873764ef7271af448dc42ab4
+      with: # All of theses inputs are optional
+        tag_name: "v%s"
+        tag_message: "v%s"
+        commit_pattern: "^Release (\\S+)"
+      env: # More info about the environment variables in the README
+        GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }} # Leave this as is, it's automatically generated
+        NPM_AUTH_TOKEN: ${{ secrets.NPM_AUTH_TOKEN }} # You need to set this in your repo settings