doc: add release process

Author: owenpearson

CONTRIBUTING.md

@@ -16,3 +16,15 @@ JavaScript/TypeScript code is:
 ## Assembly
 
 The project is built using [webpack](https://webpack.js.org/). You can build the project using `npm run build`. This will create a [minified](https://en.wikipedia.org/wiki/Minification_(programming)) JS bundle at `dist/main.js`.
+
+## Release process
+
+1. Make sure the tests are passing in CI for the branch you're building
+2. Create a new branch for the release, for example `release/1.2.3`
+3. Update the [CHANGELOG.md](./CHANGELOG.md) with any customer-affecting changes since the last release and add this to the git index
+4. Run `npm version <VERSION_NUMBER> --no-git-tag-version` with the new version and add the changes to the git index
+5. Create a PR for the release branch
+6. Once the release PR is landed to the `main` branch, checkout the `main` branch locally (remember to pull the remote changes) and run `npm run build`
+7. Run `git tag <VERSION_NUMBER>` with the new version and push the tag to git
+8. Run `npm publish .` (should require OTP) - publishes to NPM
+10. Visit https://github.com/ably/ably-asset-tracking-js/tags and add release notes to the release (you can just copy the entry you added to the CHANGELOG)