updated README

README.md

@@ -23,6 +23,18 @@ RENOVATE_TOKEN="[your token here]"
 Once this is done, you should be able to trigger a run with `npm run renovate` (or `npm run renovate:dry-run`
 for a dry run).
 
+### Using a GitHub token
+
+If you want the created Merge Requests to feature release notes from the concerned package and if said package
+is hosted on GitHub, you will have to give Renovate a GitHub API key as well, even if the project is public
+(because GitHub's API applies strict rate limiting to unauthenticated requests). To do that, go to your GitHub
+account settings and navigate to "Developer Settings", and "Personal access tokens". Create a new token (you
+don't have to give it any rights). Then, add this line to your `.env`:
+
+```dotenv
+GITHUB_PUBLIC_TOKEN="[your token here]"
+```
+
 ## Running automatically
 
 The Gitlab CI should trigger a Renovate run every day.