chore: add workflow to publish on npm

.github/workflows/publish.yml

@@ -0,0 +1,22 @@
+name: Publish to npm
+
+on:
+  push:
+    branches:
+      - main
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions/setup-node@v2
+        with:
+          node-version: '16.x'
+          registry-url: 'https://registry.npmjs.org'
+      - run: npm install
+      - run: npm run build
+      - run: npm test
+      - run: npm publish
+        env:
+          NODE_AUTH_TOKEN: ${{ secrets.NPM_TOKEN }}

package.json

@@ -1,6 +1,6 @@
 {
   "name": "dotted-map",
-  "version": "2.2.2",
+  "version": "2.2.3",
   "description": "Create a SVG map filled with dots for the world or countries",
   "main": "./index.js",
   "exports": {