Fix CI TypeError

Author: joy13975

src/ragas/executor.py

@@ -102,7 +102,7 @@ class Executor:
     keep_progress_bar: bool = True
     jobs: t.List[t.Any] = field(default_factory=list, repr=False)
     raise_exceptions: bool = False
-    run_config: t.Optional[RunConfig]
+    run_config: t.Optional[RunConfig] = field(default_factory=RunConfig, repr=False)
 
     def wrap_callable_with_index(self, callable: t.Callable, counter):
         async def wrapped_callable_async(*args, **kwargs):