Recommendations for Python on GHES (#219)

* Recommendations for Python on GHES

* Update README.md

Co-authored-by: Brian Cristante <[email protected]>

Co-authored-by: Brian Cristante <[email protected]>

Author: konradpabjan

README.md

@@ -247,6 +247,12 @@ If you are experiencing problems while configuring Python on your self-hosted ru
 
 `setup-python` helps keep your dependencies explicit and ensures consistent behavior between different runners. If you use `python` in a shell on a GitHub hosted runner without `setup-python` it will default to whatever is in PATH. The default version of Python in PATH vary between runners and can change unexpectedly so we recommend you always use `setup-python`.
 
+# 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 download that read `##[error]API rate limit exceeded for...`.
+
+To avoid hitting rate-limit problems, we recommend [setting up your own runner tool cache](https://docs.github.com/en/[email protected]/admin/github-actions/managing-access-to-actions-from-githubcom/setting-up-the-tool-cache-on-self-hosted-runners-without-internet-access#about-the-included-setup-actions-and-the-runner-tool-cache).
+
 # License
 
 The scripts and documentation in this project are released under the [MIT License](LICENSE).