[docs] update gh action v4 documentation

mkdocs/docs/install/github-action.md

@@ -56,4 +56,6 @@ If you're doing more than 5 activities a day, you will need to change the defaul
 
 ## Updating
 
-1. From the home page of your forked repository, there should be a button to `Sync fork`, click this to pull in the latest changes from the original repo
+1. Make note of your current configuration in `.github/workflows/sync_peloton_to_garmin.yml` as you may need to reapply these changes after updating.
+1. From the home page of your forked repository, there should be a button to `Sync fork`, click this to pull in the latest changes from the original repo.
+1. Go back to your `.github/workflows/sync_peloton_to_garmin.yml` and re-apply any changes from step 1.

mkdocs/docs/migration/migrate-v3-v4.md

@@ -9,6 +9,14 @@ The P2G windows exe now provides a proper user interface. You can migrate to thi
 
 There is no risk installing v4 and trying it out. Your previous install will continue to work while you test out v4.  When you're satisfied with v4 you can delete your previous version of P2G.
 
+## GitHub Action
+
+Follow the [updating instructions for GitHub Actions](../install/github-action.md#updating).  A couple notable changes that will be pulled in:
+
+1. [Container Image tag](https://github.com/philosowaffle/peloton-to-garmin/blob/v4.0.0/.github/workflows/sync_peloton_to_garmin.yml#L23) has changed to `console-stable`, you may wish to edit this to be `console-v4`
+1. The [configuration options](https://github.com/philosowaffle/peloton-to-garmin/blob/v4.0.0/.github/workflows/sync_peloton_to_garmin.yml#L40) have changed slightly with some fields being deprecated and removed
+1. The [command to run p2g](https://github.com/philosowaffle/peloton-to-garmin/blob/v4.0.0/.github/workflows/sync_peloton_to_garmin.yml#L75) has changed to `/app/ConsoleClient`.
+
 ## Docker Headless
 
 No specific migration steps are needed, however please take note of the [breaking changes](https://github.com/philosowaffle/peloton-to-garmin/releases/tag/v3.6.0) in case any of these impact your setup.

mkdocs/readme.md

@@ -12,6 +12,15 @@ Mike: https://github.com/jimporter/mike
 * `mkdocs build` - Build the documentation site.
 * `mkdocs -h` - Print help message and exit.
 
+## Updating an existing version
+
+* Checkout version of master branch that has the docs you want to modify
+* Make changes
+* `git fetch origin gh-pages --depth=1`
+* `mike deploy <version> --push`
+    * this will push to `gh-pages` branch and update the appropriate directory
+
+
 ## Project layout
 
     mkdocs.yml    # The configuration file.