update document segment (#948)

Co-authored-by: jyong <jyong@dify.ai>

api/services/dataset_service.py

@@ -973,7 +973,7 @@ class SegmentService:
                 db.session.add(segment)
                 db.session.commit()
                 # update segment vector index
-                VectorService.create_segment_vector(args['keywords'], segment, dataset)
+                VectorService.update_segment_vector(args['keywords'], segment, dataset)
         except Exception as e:
             logging.exception("update segment index failed")
             segment.enabled = False