Fix un-interpolated token

mopidy_webhooks/frontend.py

@@ -60,7 +60,7 @@ class WebhooksFrontend(pykka.ThreadingActor, CoreListener):
                 logger.info(f"No token found for Webhook URL: {webhook_url}")
 
             if token:
-                headers["Authorization"] = "Token {token}"
+                headers["Authorization"] = "Token f{token}"
 
             response = requests.post(
                 webhook_url, json=json.dumps(post_data), headers=headers