fix: Add src/auth0/py.typed to .fernignore to survive regeneration

Author: kishore7snehil

.fernignore

@@ -16,8 +16,9 @@ CHANGELOG.md
 src/auth0/authentication/
 tests/authentication/
 
-# Root auth0 __init__.py
+# Root auth0 __init__.py and py.typed marker
 src/auth0/__init__.py
+src/auth0/py.typed
 
 # Telemetry customization (Auth0 format with dynamic versioning)
 src/auth0/management/core/client_wrapper.py