Add note on 1K limit for GitHub Actions token

Author: nschonni

content/rest/overview/resources-in-the-rest-api.md

@@ -360,6 +360,8 @@ For users that belong to a {% data variables.product.prodname_ghe_cloud %} accou
 
 {% endif %}
 
+When using the built-in `GITHUB_TOKEN` in GitHub Actions, the rate limit is 1,000.
+
 For unauthenticated requests, the rate limit allows for up to 60 requests per hour. Unauthenticated requests are associated with the originating IP address, and not the user making requests.
 
 {% data reusables.enterprise.rate_limit %}