update release document

RELEASING.md

@@ -15,6 +15,6 @@
 1. When you're ready to make a new release, checkout the main branch locally and run `yarn version`
 2. Choose the new version number following [SemVer](https://semver.org/). Make sure you prefix it with `v` (`vX.Y.Z`).
     - This command creates a new commit that only updates the version in `package.json`
-3. Push this commit to the main branch
+3. Open and merge a pull request containing this commit on a new branch
 3. In GitHub's UI, navigate to Releases > "Draft New Release". Set the tag version to the version you just entered, and add a title and description for the new release
 4. Hit "Publish Release". This will trigger the `publish.yml` GitHub action, which builds a new version of the package, and publishes it to [NPM](https://www.npmjs.com/package/@datadog/sketches-js)