Update publishing instructions (#129)

The publishing instructions in the README have been updated to reflect
changes introduced in #125. We forgot to update the README in that PR.

The release instructions should now match those in the module template.

Author: Gudahtt

README.md

@@ -132,6 +132,6 @@ The project follows the same release process as the other libraries in the MetaM
 
 7. Publish the release on npm.
 
-   - Be very careful to use a clean local environment to publish the release, and follow exactly the same steps used during CI.
-   - Use `npm publish --dry-run` to examine the release contents to ensure the correct files are included. Compare to previous releases if necessary (e.g. using `https://unpkg.com/browse/[package name]@[package version]/`).
-   - Once you are confident the release contents are correct, publish the release using `npm publish`.
+   - Wait for the `publish-release` GitHub Action workflow to finish. This should trigger a second job (`publish-npm`), which will wait for a run approval by the [`npm publishers`](https://github.com/orgs/MetaMask/teams/npm-publishers) team.
+   - Approve the `publish-npm` job (or ask somebody on the npm publishers team to approve it for you).
+   - Once the `publish-npm` job has finished, check npm to verify that it has been published.