remove keep files parameter. it's not necessary, we don't use that

src/webui.py

@@ -235,7 +235,7 @@ if __name__ == '__main__':
             ref_btn.click(update_models_list, None, outputs=rvc_model)
             is_webui = gr.Number(value=1, visible=False)
             generate_btn.click(song_cover_pipeline,
-                               inputs=[main_vocals_input, backup_vocals_input, rvc_model, pitch, keep_files, is_webui, main_gain, backup_gain,
+                               inputs=[main_vocals_input, backup_vocals_input, rvc_model, pitch, is_webui, main_gain, backup_gain,
                                        inst_gain, index_rate, filter_radius, rms_mix_rate, f0_method, crepe_hop_length,
                                        protect, pitch_all, reverb_rm_size, reverb_wet, reverb_dry, reverb_damping,
                                        output_format],