Extend docu regarding rate limit issues. (#510)

Author: kasuteru

docs/advanced-usage.md

@@ -471,15 +471,29 @@ One quick way to grant access is to change the user and group of `/Users/runner/
 
 ## Using `setup-python` on GHES
 
-`setup-python` comes pre-installed on the appliance with GHES if Actions is enabled. When dynamically downloading Python distributions, `setup-python` downloads distributions from [`actions/python-versions`](https://github.com/actions/python-versions) on github.com (outside of the appliance). These calls to `actions/python-versions` are made via unauthenticated requests, which are limited to [60 requests per hour per IP](https://docs.github.com/en/rest/overview/resources-in-the-rest-api#rate-limiting). If more requests are made within the time frame, then you will start to see rate-limit errors during downloading that looks like: `##[error]API rate limit exceeded for...`.
+### Avoiding rate limit issues
 
-To get a higher rate limit, you can [generate a personal access token on github.com](https://github.com/settings/tokens/new) and pass it as the `token` input for the action:
+`setup-python` comes pre-installed on the appliance with GHES if Actions is enabled. When dynamically downloading Python distributions, `setup-python` downloads distributions from [`actions/python-versions`](https://github.com/actions/python-versions) on github.com (outside of the appliance). These calls to `actions/python-versions` are by default made via unauthenticated requests, which are limited to [60 requests per hour per IP](https://docs.github.com/en/rest/overview/resources-in-the-rest-api#rate-limiting). If more requests are made within the time frame, then you will start to see rate-limit errors during downloading that look like this: 
+
+    ##[error]API rate limit exceeded for YOUR_IP. (But here's the good news: Authenticated requests get a higher rate limit. Check out the documentation for more details.)
+
+To get a higher rate limit, you can [generate a personal access token (PAT) on github.com](https://github.com/settings/tokens/new) and pass it as the `token` input for the action. It is important to understand that this needs to be a token from github.com and _not_ from your GHES instance. If you or your colleagues do not yet have a github.com account, you might need to create one.
+
+Here are the steps you need to follow to avoid the rate limit:
+
+1. Create a PAT on any github.com account by using [this link](https://github.com/settings/tokens/new) after logging into github.com (not your Enterprise instance).  This PAT does _not_ need any rights, so make sure all the boxes are unchecked.
+2. Store this PAT in the repository / organization where you run your workflow, e.g. as `GH_GITHUB_COM_TOKEN`. You can do this by navigating to your repository -> **Settings** -> **Secrets** -> **Actions** -> **New repository secret**.
+3. To use this functionality, you need to use any version newer than `v4.3`. Also, change _python-version_ as needed.
 
 ```yml
-uses: actions/setup-python@v4
-with:
-  token: ${{ secrets.GH_DOTCOM_TOKEN }}
-  python-version: 3.11
+- name: Set up Python
+  uses: actions/setup-python@4
+  with:
+    python-version: 3.8
+    token: ${{ secrets.GH_GITHUB_COM_TOKEN }}
 ```
 
+Requests should now be authenticated. To verify that you are getting the higher rate limit, you can call GitHub's [rate limit API](https://docs.github.com/en/rest/rate-limit) from within your workflow ([example](https://github.com/actions/setup-python/pull/443#issuecomment-1206776401)).
+
+### No access to github.com
 If the runner is not able to access github.com, any Python versions requested during a workflow run must come from the runner's tool cache. See "[Setting up the tool cache on self-hosted runners without internet access](https://docs.github.com/en/enterprise-server@3.2/admin/github-actions/managing-access-to-actions-from-githubcom/setting-up-the-tool-cache-on-self-hosted-runners-without-internet-access)" for more information.