Adapt custom header name

Author: FlorentinD

graphdatascience/query_runner/gds_arrow_client.py

@@ -237,7 +237,7 @@ def __init__(self, useragent: str, *args: Any, **kwargs: Any) -> None:
         self._useragent = useragent
 
     def sending_headers(self) -> Dict[str, str]:
-        return {"gds-user-agent": self._useragent}
+        return {"x-gds-user-agent": self._useragent}
 
     def received_headers(self, headers: Dict[str, Any]) -> None:
         pass