Fix PAT instructions with Dependabot

Author: github-actions[bot]

README.md

@@ -452,10 +452,12 @@ If you create a fine-grained personal access token, apply the `Contents`-permiss
 ```yaml
 - uses: actions/checkout@v4
   with:
-    token: ${{ secrets.PAT }}
+    token: ${{ secrets.PAT || secrets.GITHUB_TOKEN }}
 ```
 You can learn more about Personal Access Token in the [GitHub documentation](https://docs.github.com/en/github/authenticating-to-github/creating-a-personal-access-token).
 
+Having a fallback to GITHUB_TOKEN helps things like Dependabot to continue working, as they may not be granted access to the PAT.
+
 > [!TIP] 
 > If you're working in an organisation, and you don't want to create the PAT from your personal account, we recommend using a bot-account for such tokens.