add publish flow

.github/workflows/npm-publish.yml

@@ -0,0 +1,20 @@
+name: publish npm package
+
+on:
+  workflow_dispatch
+
+jobs:
+  publish:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - uses: actions/setup-node@v3
+        with:
+          node-version: "18"
+      - run: npm ci
+      - run: npm run build
+      - uses: JS-DevTools/npm-publish@v2
+        with:
+          token: ${{ secrets.NPM_TOKEN }}
+      - if: ${{ steps.publish.outputs.type }}
+        run: echo "Version changed!"