refactor: Update auth_headers method to return an empty dictionary

Author: Ahmedhossamdev

src/onebusaway/_client.py

@@ -134,8 +134,9 @@ def qs(self) -> Querystring:
         return Querystring(array_format="repeat")
 
     @property
-    def auth_headers(self) -> httpx.Auth:
-        raise NotImplementedError("This auth method has not been implemented yet.")
+    @override
+    def auth_headers(self) -> dict[str, str]:
+        return {}
 
     @property
     @override
@@ -329,8 +330,9 @@ def qs(self) -> Querystring:
         return Querystring(array_format="repeat")
 
     @property
-    def auth_headers(self) -> httpx.Auth:
-        raise NotImplementedError("This auth method has not been implemented yet.")
+    @override
+    def auth_headers(self) -> dict[str, str]:
+        return {}
 
     @property
     @override