Document the release workflow steps

Author: jasonkarns

docs/CONTRIBUTING.md

@@ -10,4 +10,7 @@ https://docs.github.com/en/communities/setting-up-your-project-for-healthy-contr
 
 From a clean working copy, run `npm version major|minor|patch|VERSION`.
 This will bump the package version, commit, tag, and push.
-The tag-push event triggers the release workflow on GitHub.
+
+The tag-push event triggers the release workflow on GitHub, which creates a
+GitHub Release for the tag. It also (when applicable) publishes to npm and
+opens a pull request to bump the corresponding formula in its Homebrew tap.