added link to verify_signature

app.py

@@ -30,6 +30,7 @@ def webhook():
 
 
 
+# https://docs.github.com/en/enterprise-server@3.6/webhooks-and-events/webhooks/securing-your-webhooks#python-example
 def verify_signature(payload_body, signature_header, secret_token):
     """Verify that the payload was sent from GitHub by validating SHA256.