Add Github action for package publishing, fix prepublish script

.github/workflows/publish.yml

@@ -0,0 +1,17 @@
+name: Publish Denomo to NPM
+on:
+  release:
+    types: [published]
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions/setup-node@v2
+        with:
+          node-version: 16
+          registry-url: 'https://registry.npmjs.org'
+      - run: npm ci
+      - run: npm publish
+        env:
+          NODE_AUTH_TOKEN: ${{ secrets.NPM_TOKEN }}

package.json

@@ -14,7 +14,7 @@
   "scripts": {
     "build": "tsc",
     "lint": "eslint",
-    "prepublish": "npm run build",
+    "prepublishOnly": "npm run build",
     "pretest": "npm run build",
     "test": "mocha \"build/tests/*.spec.js\""
   },