Hi Amit,
as far as I can see in your file, you try to call gulp watch, this will call the task 'gulp.upload' which is commented out.
Also the gulp.upload task is trying to perform the tasks parallel ( gulp.parallel ) which could cause problems, because you want to delete the existing theme (in Confluence) first before uploading your new files.
So I would recommend to use the [array] as it is in the default gulp files from ours.
Hope this is helping.
Let me know if you encounter any problems.
Best Regards,
Steffen