change output type of upsscale

pipeline.py

@@ -1201,7 +1201,7 @@ class StableDiffusionLongPromptWeightingPipeline(StableDiffusionPipeline):
                                       eta=eta,
                                       generator=generator,
                                       max_embeddings_multiples=max_embeddings_multiples,
-                                      output_type=output_type,
+                                      output_type="pil",
                                       return_dict=return_dict,
                                       callback=callback,
                                       is_cancelled_callback=is_cancelled_callback,