Set up automated npm publish

.github/workflows/publish-on-tag.yml

@@ -0,0 +1,28 @@
+name: publish-on-tag
+
+on:
+  push:
+    tags:
+    - '*'
+
+jobs:
+  publish:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+      - name: Set up Node.js
+        uses: actions/setup-node@v3
+        with:
+          node-version-file: '.nvmrc'
+      - name: Install dependencies
+        run: npm install
+      - name: Test
+        run: npm test
+      - name: Publish
+        env:
+          NPM_TOKEN: ${{secrets.NPM_TOKEN}}
+        run: |
+          npm config set registry 'https://wombat-dressing-room.appspot.com/'
+          npm config set '//wombat-dressing-room.appspot.com/:_authToken' '${NPM_TOKEN}'
+          npm publish

.nvmrc

@@ -0,0 +1 @@
+18

README.md

@@ -1,4 +1,4 @@
-# ES6 `String.prototype.codePointAt` polyfill [![Build status](https://travis-ci.org/mathiasbynens/String.prototype.codePointAt.svg?branch=master)](https://travis-ci.org/mathiasbynens/String.prototype.codePointAt)
+# ES6 `String.prototype.codePointAt` polyfill  [![string.prototype.codepointat on npm](https://img.shields.io/npm/v/string.prototype.codepointat)](https://www.npmjs.com/package/string.prototype.codepointat)
 
 A robust & optimized polyfill for [the `String.prototype.codePointAt` method in ECMAScript 6](http://people.mozilla.org/~jorendorff/es6-draft.html#sec-string.prototype.codepointat).
 
@@ -42,6 +42,28 @@ In a browser:
 
 [A polyfill + test suite for `String.fromCodePoint`](https://mths.be/fromcodepoint) is available, too.
 
+## For maintainers
+
+### How to publish a new release
+
+1. On the `main` branch, bump the version number in `package.json`:
+
+    ```sh
+    npm version patch -m 'Release v%s'
+    ```
+
+    Instead of `patch`, use `minor` or `major` [as needed](https://semver.org/).
+
+    Note that this produces a Git commit + tag.
+
+1. Push the release commit and tag:
+
+    ```sh
+    git push && git push --tags
+    ```
+
+    Our CI then automatically publishes the new release to npm.
+
 ## Author
 
 | [![twitter/mathias](https://gravatar.com/avatar/24e08a9ea84deb17ae121074d0f17125?s=70)](https://twitter.com/mathias "Follow @mathias on Twitter") |