[func] add action to publish to npm

Author: Piou-piou

.github/workflows/npmpublish.yml

@@ -0,0 +1,45 @@
+name: Publish package
+
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+    branches: [ master ]
+
+jobs:
+  publish-npm:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+        with:
+          ref: master
+        
+      - name: Npm install
+        uses: actions/setup-node@v1
+        with:
+          node-version: 12
+      - run: npm install
+      
+      - name: Check if version has been updated
+        uses: EndBug/version-check@v1
+        id: check
+
+      - name: Log when changed
+        if: steps.check.outputs.changed == 'true'
+        run: 'echo "Version change found in commit ${{ steps.check.outputs.commit }}! New version: ${{ steps.check.outputs.version }} (${{ steps.check.outputs.type }})"'
+
+      - name: Log when unchanged
+        if: steps.check.outputs.changed != 'true'
+        run: 'echo "Version unchanged"'
+
+      - name: Set up Node.js for NPM
+        uses: actions/setup-node@v1
+        with:
+          registry-url: "https://registry.npmjs.org"
+
+      - name: Publish package to NPM
+        if: steps.check.outputs.changed == 'true'
+        run: npm publish
+        env:
+          NODE_AUTH_TOKEN: ${{ secrets.npm_token }}