doc: include git node release --promote to steps

doc/contributing/releases.md

@@ -704,12 +704,23 @@ the build before moving forward. Use the following list as a baseline:
 
 ### 11. Tag and sign the release commit
 
-Once you have produced builds that you're happy with, create a new tag. By
-waiting until this stage to create tags, you can discard a proposed release if
-something goes wrong or additional commits are required. Once you have created a
-tag and pushed it to GitHub, you _**must not**_ delete and re-tag. If you make
-a mistake after tagging then you'll have to version-bump and start again and
-count that tag/version as lost.
+Once you have produced builds that you're happy with you can either run
+`git node release --promote`
+
+```bash
+git node release -S --promote https://github.com/nodejs/node/pull/XXXX
+```
+
+to automate the remaining steps until step 16 or you can perform it manually
+following the below steps.
+
+***
+
+Create a new tag: By waiting until this stage to create tags, you can discard
+a proposed release if something goes wrong or additional commits are required.
+Once you have created a tag and pushed it to GitHub, you _**must not**_ delete
+and re-tag. If you make a mistake after tagging then you'll have to version-bump
+and start again and count that tag/version as lost.
 
 Tag summaries have a predictable format. Look at a recent tag to see: