✏ Fix broken link to newsletter sign-up in docs/help.md (#84)

Co-authored-by: Sebastián Ramírez <[email protected]>

Author: mborus

docs/help.md

@@ -12,7 +12,7 @@ And there are several ways to get help too.
 
 ## Subscribe to the FastAPI and Friends newsletter
 
-You can subscribe to the (infrequent) [**FastAPI and friends** newsletter](/newsletter/){.internal-link target=_blank} to stay updated about:
+You can subscribe to the (infrequent) <a href="https://fastapi.tiangolo.com/newsletter" class="external-link" target="_blank">**FastAPI and friends** newsletter</a> to stay updated about:
 
 * News about FastAPI and friends, including SQLModel 🚀
 * Guides 📝