docs: add mkdocs gh-deploy info

Author: grokify

Diff for: README.md

@@ -13,7 +13,7 @@ It covers:
 1. Day 2 deployment information for [automating packaging](https://grokify.github.io/fastly-guide-compute/compute/packaging/)
 2. Day 2 deployment information for [API and SDK upload and activation options](https://grokify.github.io/fastly-guide-compute/compute/uploading_and_activation/)
 
-## Running the Guide Locally
+## Running the Guide Locally (for authors)
 
 This Developer Guide is built on top of Mkdocs, a self-contained documentation server. Writers are encouraged to install Mkdocs locally so that you can edit files and preview your changes before they are pushed to production servers.
 
@@ -25,4 +25,12 @@ pip install --upgrade mkdocs-material
 mkdocs serve
 ```
 
-Then you should be able to load http://localhost:8000 to view the documentation.
+Then you should be able to load http://localhost:8000 to view the documentation.
+
+## Deploying the Guide
+
+Once the updates have been made, use the following command to publish to GitHub pages:
+
+```bash
+mkdocs gh-deploy
+```